8.1L install into 1978 K10…DONE

[JCampbell]

Kick ass. Thanks, Brother!

[JCampbell]

One more thing...I thought I heard that at a certain point, GM eliminated the EGR on these engines.

Hear anything about that?

[DirtyLarry]

Originally Posted by JCampbell

One more thing...I thought I heard that at a certain point, GM eliminated the EGR on these engines.

Hear anything about that?

Yep, that is true. 2004 brought a few changes to the 8.1L being the four big changes where a returnless fuel rail, EGR elimination and updated cam and crank sensors. My engine is actually a 2002 but I run some 2005 parts on it including the EGR block off plate. Howell tuned the ECM to turn off EGR, Torque Management and the electronic throttle pedal. Mine also runs the return type fuel rail, which is kind of a hassle to plumb one more line from tank to the engine but in my opinion it is worth it as the return type fuel rail has an adjustable fuel regulator built into it. The 8.1L loves higher fuel pressure than the spec of 62 psi, mine is set at 68 psi. It was a noticeable gain in power by bumping up the fuel pressure with no change in fuel economy. It does smell a bit fat at idle and runs like a scalded dog at WOT. This bone stock 8.1L with some ECM tuning and a bump in fuel pressure will run circles around the bored and whored 396 in my '68 GMC.

Here is the 2004 L18 GM Powertrain product summary

Vortec 8100 8.1L V-8 (L18)

2004 Model Year Summary
• Returnless fuel injection for Chevrolet Avalanche, Silverado and Suburban, GMC Sierra and Yukon XL and Workhorse Custom Chassis
• Low permeability intake manifold body gaskets
• Improved onboard refueling vapor recovery (ORVR) system for Avalanche, Silverado, Suburban, Sierra and Yukon XL
• Exhaust gas recirculation (EGR) eliminated
• Improved crank and cam timing sensors
• Improved crankshaft seal
• Adjustable throttle pedal for Workhorse Custom Chassis
• Revised cylinder heads for industrial applications


FULL DESCRIPTIONS OF NEW OR CHANGED FEATURES

RETURNLESS FUEL INJECTION FOR CHEVROLET AVALANCHE, SILVERADO AND SUBURBAN, GMC SIERRA AND YUKON XL AND WORKHORSE CUSTOM CHASSIS
All Vortec 8100s built for these applications are equipped with a new "returnless" fuel injection system that eliminates fuel return lines between the engine and the gasoline tank. The new fuel system is also known as a demand system.

Before model year 2004, the Vortec 8100’s sequential fuel injection (SFI) used a return line to manage fuel pressure by bleeding off excess fuel at the fuel rail and returning the excess to the tank. The new system eliminates the return lines and moves the fuel-pressure regulator from the fuel rail on the engine to the fuel tank. The fuel line from the tank now includes pulse dampeners, or a series of baffles, that manage fuel pulsing and limit noise.

Because it delivers only the amount of fuel need by the injectors, and returns no fuel to the gas tank, the returnless system essentially eliminates heat transfer from the engine to tank. This reduces the amount of vapor generated in the tank, and captured by the evaporative emissions control system.

Vortec 8100s built for the medium-duty Chevrolet Kodiak and GMC Topkick, as well as those built for marine and industrial applications, continue with fuel injection managed with return lines.

LOW PERMEABILITY INTAKE MANIFOLD AND THROTTLE BODY GASKETS
The Vortec 8100 has new intake manifold sealing gaskets manufactured from a fluorocarbon material. These fluorocarbon gaskets represent the best sealing technology available. The gaskets are resistant to most chemicals, for maximum durability, and particularly impermeable to small hydrocarbon molecules. Gasoline vapor cannot penetrate the fluorocarbon. Moreover, the gaskets are designed to improve sealing for the life of the engine. They are molded with slight protrusions, or ``snouts,’’ that fit into counter-bores milled in the cylinder heads. The snouts more positively locate the gaskets and virtually eliminate the possibility of movement during assembly or after repeated thermal cycling over the life of the engine.

IMPROVED ONBOARD REFUELING VAPOR RECOVERY (ORVR) SYSTEM FOR CHEVROLET AVALANCHE AND SILVERADO, GMC SIERRA AND YUKON XL
The ORVR system on these Vortec 8100-equipped vehicles uses a new evaporative emissions canister and purge-control solenoid. ORVR reduces evaporative emissions by preventing gasoline vapor from escaping into the atmosphere during refueling. These new ORVR components take full advantage of advanced technology built into the Vortec 8100's P59 Powertrain Control Module (PCM). The PCM and new components more efficiently manage ORVR, and improve the accuracy and robustness of the OBDII (On-Board Diagnostics) system.

[JCampbell]

Thanks!

[Smoke_Dog]

Man!!!!

[RatRod68]

So freaking awesome. I drooled over most of the pictures in your album and over on mooseburbs thread. I do have a question though, what kind of fuel economy are you getting? I know these engines get much better milage than the LQ4/9 when towing and when both engines are stock, but i was wondering about one with the Howell setup. I used Howell for my swap as well. They really have some great products.

Also, how do you like the NV4500 over something like a 4L80E? Are you always upshifting and downshifting?

I like the way you have it setup now. Looks just awesome. What color blue is that?

[DirtyLarry]

Thanks!

Fuel economy isn’t that bad for what it is. The last big trip we did (with Mosesburb) was 1,555 miles which included highway driving over mountain passes, low speed/low RPM desert exploration in Utah and Colorado trail riding with low speed/moderate RPM steep mountain crawling for two straight days. The truck weighted in right at 8,100 lbs. for this trip and ran with A/C on most of the time. The MPG for the entire trip was 11.72 MPG. That is not great but for a truck with 425 HP/550 lb ft of torque and weighting 8,000lbs with the aerodynamics of a drive in movie theater screen, I don’t that that is too bad. My stock ’01 Silverado with an 8.1L doesn’t do much better and my old 6.0L Silverado definitely wouldn’t do that good if it weighed anywhere near 8,000 lbs. The 8.1L has a lot more low end torque over a 6.0L but the 6.0L does feel seat-of-the pants “quicker” and more athletic sprinting around town when it is unloaded in a light truck. Add a load behind a 6.0L and it becomes a snail.

I am not a much of an automatic trans kind of guy. The NV4500 5 speed works very well with a tuned 8.1L as it gives the powertrain more of a diesel like personality where it has gobs of low end torque and does very well lugging with very low RPM shifting. I often shift this thing just off idle at 1,200 to 1,500 RPM’s where it still pulls extremely well. Again, these 8.1L’s have awesome low end diesel like torque but when it comes time to get nasty it doesn’t mind being poked in the neck and ran up to 6,000 RPM’s if you want to scat quickly. I seldom shift above 2,500 RPM's because the exhaust gets so LOUD (I must be getting old ) and the rear Detroit Locker causes the truck to swerve all over the road. With the low end torque of this engine I do not shift often in traffic. I just lug it around. It also has no problem passing on the highway making quick passes going from 55 to 85 MPH without ever shifting out of 5th gear….even with the camper on the truck.

If you driven an 8.1L in a Silverado forget about it. You must drive one that has been tuned with torque management turned off, high performance tune added, bump in fuel pressure, etc. A tweaked 8.1L runs like a completely different animal than a stock 8.1L in a Silverado. For a 4x4 I’ll take an 8.1L over a 6.0L any day and still have more usable power with the same, if not better, fuel economy plus the 8.1L is an easier swap.

The blue is a 1998 Pontiac Montana mini-van Quasar Blue. Some of the paint colors were the only thing worth the hoot on those horrid mini-vans.

[Mr. 250r]

Just wondering whats considered the 'drama' in the ls swap, not trying to start an argument or anything i was just curious as the swap differences

[DirtyLarry]

Originally Posted by Mr. 250r

Just wondering whats considered the 'drama' in the ls swap, not trying to start an argument or anything i was just curious as the swap differences

That is the glory of GM engines, there really isn’t any “drama” with doing any late model swaps regardless which late model engine a person choses to use. I personally find the 8.1L an easier swap for the following reasons:

Engine mounting:
8.1L – Direct bolt in. The engine sits in the same exact location, with the same exact engine mount bosses located in the block where they are found on old small or big blocks. You may reuse the old small or big block engine mounts and saddles. 4x4’s do require an ORD engine crossmember to clear the large 8.1L oil pan but the OEM crossmember can be modified if one wanted go that route.

LS – Engine mount adapters are required

Exhaust:
8.1L – direct bolt in when replacing any older big block. Existing exhaust manifolds or headers may be reused on the 8.1L. No need to spend money reworking the exhaust system. If going from an small block to a 8.1L, it is the same process people have been doing for past 47 years to swap in a big block.

LS – Depending on the chassis (2wd or 4wd) and transmission combination finding the correct exhaust manifold or header to fit a project vehicle can be a challenge and expensive.

Accessories:
8.1L – Uses the typical GM 168 tool flywheel with the typical older small and big block starter mounting design with the staggered starter bolts. No need to buy a new starter motor if swapping from an old small or big block.

LS – Uses a unique starter mounting design where a new starter with side by side starter bolts must be used when swapping in a LS. Adds cost to a swap.

8.1L – When using the correct accessory brackets (RV or G-Van), the A/C compressor can be mounted up high making A/C line connections much easier. No need to hack a chunk out of the frame to make room for the A/C compressor. There are a few OEM options with slightly different designs for 8.1L bracketry; Pickups, G-vans, RVs, Medium Duty trucks and Marine. Most people are only aware of pickup design 8.1L accessory brackets as they are the most well known. As luck would have it, pickup truck brackets are the worst to use due to the location of the A/C compressor (same front lower RH of engine as the LS).

LS- No options for accessory brackets outside of the aftermarket. The A/C compressor gets stuffed in the RH corner of the frame rail making line connections a hassle. Some people even hack out a chunk of the top frame section for A/C compressor clearance.

Cooling:
8.1L – The upper radiator hose neck is on the driver’s side and lines up nicely with the old radiators. The lower hose location at the water pump is in the same location as any older small or big block. Same ole BB lower radiator hose too.

LS – The upper radiator hose neck is on the passenger’s side requiring a goofy looking upper radiator hose to cross over the fan shroud or radiator support to the driver’s side. Factory GM trucks with LS engines have the same goofy arrangement. Me no likey!

These are just a couple quick things I could think off the top of my head. None of these are huge deal stopper “drama” things that aren’t easily resolved. It is just my opinion the 8.1L is easier to swap compared to LS. I am sure there are LS swappers here that feed quite the contrary to my opinion while others will agree and may even have more time and money costing things related to LS swaps.

I haven’t added any new pictures of my 8.1L in a while. This is how it currently looks after reworking the air induction pipe this past July. Thanks to Blake in the 73-87 project forum for this cool air induction pipe recipe! The truck has about 15,000 miles on it now since the 8.1L was installed in 2008.

[Mr. 250r]

I feel its roughly the same except the exhaust and ac i didn't have all the problems listed as i used my stock cross member and starter with no mods as far as the 8.1s go i never see them go for cheap and i was never a big block fan =-p but when it comes to boats and big blocks you can count me in, especially mercury's 1350s

But i guess we both agree a late model motor is a great swap

[RatRod68]

Originally Posted by DirtyLarry

Thanks!

Fuel economy isn’t that bad for what it is. The last big trip we did (with Mosesburb) was 1,555 miles which included highway driving over mountain passes, low speed/low RPM desert exploration in Utah and Colorado trail riding with low speed/moderate RPM steep mountain crawling for two straight days. The truck weighted in right at 8,100 lbs. for this trip and ran with A/C on most of the time. The MPG for the entire trip was 11.72 MPG. That is not great but for a truck with 425 HP/550 lb ft of torque and weighting 8,000lbs with the aerodynamics of a drive in movie theater screen, I don’t that that is too bad. My stock ’01 Silverado with an 8.1L doesn’t do much better and my old 6.0L Silverado definitely wouldn’t do that good if it weighed anywhere near 8,000 lbs. The 8.1L has a lot more low end torque over a 6.0L but the 6.0L does feel seat-of-the pants “quicker” and more athletic sprinting around town when it is unloaded in a light truck. Add a load behind a 6.0L and it becomes a snail.

I wouldn't go as far to say a snail, but you can feel it back there. With my explorer and gear loaded, my trailer weighs in around 9500-10000lbs, and my dad's silverado (02 2500 HD 6.0 auto) pulls that thing with NO problems, other than fuel. I average 8-10 when towing with the HD, but that's also driving 70-75 on the interstates.


I am not a much of an automatic trans kind of guy. The NV4500 5 speed works very well with a tuned 8.1L as it gives the powertrain more of a diesel like personality where it has gobs of low end torque and does very well lugging with very low RPM shifting. I often shift this thing just off idle at 1,200 to 1,500 RPM’s where it still pulls extremely well. Again, these 8.1L’s have awesome low end diesel like torque but when it comes time to get nasty it doesn’t mind being poked in the neck and ran up to 6,000 RPM’s if you want to scat quickly. I seldom shift above 2,500 RPM's because the exhaust gets so LOUD (I must be getting old ) and the rear Detroit Locker causes the truck to swerve all over the road. With the low end torque of this engine I do not shift often in traffic. I just lug it around. It also has no problem passing on the highway making quick passes going from 55 to 85 MPH without ever shifting out of 5th gear….even with the camper on the truck.

If you driven an 8.1L in a Silverado forget about it. You must drive one that has been tuned with torque management turned off, high performance tune added, bump in fuel pressure, etc. A tweaked 8.1L runs like a completely different animal than a stock 8.1L in a Silverado. For a 4x4 I’ll take an 8.1L over a 6.0L any day and still have more usable power with the same, if not better, fuel economy plus the 8.1L is an easier swap.

I've never driven one, only word of mouth reviews. Sounds about the same as a tuned LS motor. stock, they are great engines, but tuned, they are FRICKING AWESOME engines. How much did it cost (not including the engine) to install your setup?

The blue is a 1998 Pontiac Montana mini-van Quasar Blue. Some of the paint colors were the only thing worth the hoot on those horrid mini-vans.

I think that blue is gorgeous. The vans, not so much

Originally Posted by DirtyLarry

That is the glory of GM engines, there really isn’t any “drama” with doing any late model swaps regardless which late model engine a person choses to use. I personally find the 8.1L an easier swap for the following reasons:

Engine mounting:
8.1L – Direct bolt in. The engine sits in the same exact location, with the same exact engine mount bosses located in the block where they are found on old small or big blocks. You may reuse the old small or big block engine mounts and saddles. 4x4’s do require an ORD engine crossmember to clear the large 8.1L oil pan but the OEM crossmember can be modified if one wanted go that route.

LS – Engine mount adapters are required

Also need a different pan if you go with an engine from a car
Exhaust:
8.1L – direct bolt in when replacing any older big block. Existing exhaust manifolds or headers may be reused on the 8.1L. No need to spend money reworking the exhaust system. If going from an small block to a 8.1L, it is the same process people have been doing for past 47 years to swap in a big block.

LS – Depending on the chassis (2wd or 4wd) and transmission combination finding the correct exhaust manifold or header to fit a project vehicle can be a challenge and expensive.

Had to notch the frame to keep the factory manifolds, and build a completely new exhaust.

Accessories:
8.1L – Uses the typical GM 168 tool flywheel with the typical older small and big block starter mounting design with the staggered starter bolts. No need to buy a new starter motor if swapping from an old small or big block.

LS – Uses a unique starter mounting design where a new starter with side by side starter bolts must be used when swapping in a LS. Adds cost to a swap.

8.1L – When using the correct accessory brackets (RV or G-Van), the A/C compressor can be mounted up high making A/C line connections much easier. No need to hack a chunk out of the frame to make room for the A/C compressor. There are a few OEM options with slightly different designs for 8.1L bracketry; Pickups, G-vans, RVs, Medium Duty trucks and Marine. Most people are only aware of pickup design 8.1L accessory brackets as they are the most well known. As luck would have it, pickup truck brackets are the worst to use due to the location of the A/C compressor (same front lower RH of engine as the LS).

LS- No options for accessory brackets outside of the aftermarket. The A/C compressor gets stuffed in the RH corner of the frame rail making line connections a hassle. Some people even hack out a chunk of the top frame section for A/C compressor clearance.

Now this is where I have to disagree, only to inform, not to insult. There are different accessory brackets on vans, F-body cars, corvettes, and trucks. Although, with each one of those, the A/C is still down low where you will have to chunk the frame. Just wanted to give light to the other brackets that are available out there

Cooling:
8.1L – The upper radiator hose neck is on the driver’s side and lines up nicely with the old radiators. The lower hose location at the water pump is in the same location as any older small or big block. Same ole BB lower radiator hose too.

LS – The upper radiator hose neck is on the passenger’s side requiring a goofy looking upper radiator hose to cross over the fan shroud or radiator support to the driver’s side. Factory GM trucks with LS engines have the same goofy arrangement. Me no likey!

It is ugly, and it requires an inline vent hose from the heads to be plumbed

These are just a couple quick things I could think off the top of my head. None of these are huge deal stopper “drama” things that aren’t easily resolved. It is just my opinion the 8.1L is easier to swap compared to LS. I am sure there are LS swappers here that feed quite the contrary to my opinion while others will agree and may even have more time and money costing things related to LS swaps.

I haven’t added any new pictures of my 8.1L in a while. This is how it currently looks after reworking the air induction pipe this past July. Thanks to Blake in the 73-87 project forum for this cool air induction pipe recipe! The truck has about 15,000 miles on it now since the 8.1L was installed in 2008.

The mileage is extremely respectable considering the weight and aerodynamics of this rig.

[DirtyLarry]

Originally Posted by RatRod68

The mileage is extremely respectable considering the weight and aerodynamics of this rig.

Cost for the swap is ever evolving. My first mistake was starting with a GM Performance Parts MEFI-4 ECM which is the ECM used on RamJet engines and Marine applications. I could never get that system to run right so after running that for over a year I replaced that engine management system with a Howell Harness to move to a MAF system running a GM P59 ECM. The cost for the 8.1L swap was around $1800 including the old MEFI-4 system then later changing it to a P59 as well as the recent change in the air induction piping. Had I started with a Howell Harness in the beginning, the cost would have been about half. I reused all of my old accessories from a 454HO so there was no expense there.

Hehe, my experience with towing with a 6.0L was more like a snail. A few years ago I bought a used beater 2005 2500HD 4x4 bare bones regular cab truck for half of what NADA value was listed at the time. The sole purpose was to fix it and flip it, which I eventually did and made a little money on it. With having both a 6.0L and an 8.1L Silverado at the same time it was easy to compare the two. Both even had the same gear ratio (4:10 and tire diameter but the 6.0L truck was an automatic). I towed a Jeep Grand Cherokee on a car trailer from COS to Pueblo with the 6.0L truck one day. It was a snail that would barely hold overdrive on the highway and drank gas like crazy. It had very little low end grunt where it really didn’t make any usable power until ridiculous high RPMs...unloaded it was a different story, the truck would run circles around the 8.1L Silverado from stop light to stop light. Towing, not so much.

I hear you on the different brackets for the LS, my point was there isn’t any major differences in LS bracketry to move the A/C compressor. The differences between truck, van and car LS engine brackets is pretty small where only the alternator moves a bit.

Check out this cool label my buddy BeamN7 made! He made the artwork then I found a graphic supplier to make the decals. Everybody that sees this has to take a double take

[Ski-me]

Excellent job and can't believe how "factory" it really does look in that engine bay. Very sharp!

So I have the 8.1L in my 2004 suburban and have heard that it's been de-tuned from the factory. Are you suggesting that I do have some "unreleased" power in there somewhere?!? I do love the way the truck tows and in my experience, more snappy than the 6.0L....but there's more? Please share

[DirtyLarry]

Originally Posted by Ski-me

Excellent job and can't believe how "factory" it really does look in that engine bay. Very sharp!

So I have the 8.1L in my 2004 suburban and have heard that it's been de-tuned from the factory. Are you suggesting that I do have some "unreleased" power in there somewhere?!? I do love the way the truck tows and in my experience, more snappy than the 6.0L....but there's more? Please share

Thanks!

Ah yeah, there is more power to be pulled out of the late model Vortec’s in tuning and mainly, turning off torque management. I hear great things about Nelson Tuning but have never tried theirs personally. Howell does a pretty good job of tuning as well. If El Paso County is still an emission testing county you may want to grab an extra ECM to have tuned that way you can keep your stock ECM to plug in the day of emissions testing. I have friends in Denver that do that.

[RatRod68]

Originally Posted by DirtyLarry

Cost for the swap is ever evolving. My first mistake was starting with a GM Performance Parts MEFI-4 ECM which is the ECM used on RamJet engines and Marine applications. I could never get that system to run right so after running that for over a year I replaced that engine management system with a Howell Harness to move to a MAF system running a GM P59 ECM. The cost for the 8.1L swap was around $1800 including the old MEFI-4 system then later changing it to a P59 as well as the recent change in the air induction piping. Had I started with a Howell Harness in the beginning, the cost would have been about half. I reused all of my old accessories from a 454HO so there was no expense there.

Hehe, my experience with towing with a 6.0L was more like a snail. A few years ago I bought a used beater 2005 2500HD 4x4 bare bones regular cab truck for half of what NADA value was listed at the time. The sole purpose was to fix it and flip it, which I eventually did and made a little money on it. With having both a 6.0L and an 8.1L Silverado at the same time it was easy to compare the two. Both even had the same gear ratio (4:10 and tire diameter but the 6.0L truck was an automatic). I towed a Jeep Grand Cherokee on a car trailer from COS to Pueblo with the 6.0L truck one day. It was a snail that would barely hold overdrive on the highway and drank gas like crazy. It had very little low end grunt where it really didn’t make any usable power until ridiculous high RPMs...unloaded it was a different story, the truck would run circles around the 8.1L Silverado from stop light to stop light. Towing, not so much.

I hear you on the different brackets for the LS, my point was there isn’t any major differences in LS bracketry to move the A/C compressor. The differences between truck, van and car LS engine brackets is pretty small where only the alternator moves a bit.

Check out this cool label my buddy BeamN7 made! He made the artwork then I found a graphic supplier to make the decals. Everybody that sees this has to take a double take

Wow. A lot cheaper than the LS swap. Granted, I moved my tank from behind the cab to under the bed, and that accounted for a pretty good chunk, but still. The harness and PCM program was 1600.00 alone for the LS/4L60E. I think the 73-91 series trucks can use their stock tank, and I am sure the 67-72's can as well, but i'm not sure

Wow, that is crazy to hear about the 6L. I will say that it takes a little bit to get moving, but once that thing is on the interstate, look out! Although I have heard that if you stay around 55-70 range, its always downshifting and upshifting when towing. Gives me an excuse to the tell the ol lady we have to go faster

That's a really cool sticker!

[Ski-me]

Originally Posted by DirtyLarry

Thanks!

Ah yeah, there is more power to be pulled out of the late model Vortec’s in tuning and mainly, turning off torque management. I hear great things about Nelson Tuning but have never tried theirs personally. Howell does a pretty good job of tuning as well. If El Paso County is still an emission testing county you may want to grab an extra ECM to have tuned that way you can keep your stock ECM to plug in the day of emissions testing. I have friends in Denver that do that.

Appreciate it, thanks! We haven't done emissions for a few years now so I guess they've dropped that.

[68GMCburban]

I know this is an old thread, but I'm looking at doing an 8.1 swap in my 68 suburban. Will it sit down in there just like it did in your Blazer, being that they are different body styles? I haven't been able to find anything on here about somebody putting one into a 67-72.

[RatRod68]

Originally Posted by 68GMCburban

I know this is an old thread, but I'm looking at doing an 8.1 swap in my 68 suburban. Will it sit down in there just like it did in your Blazer, being that they are different body styles? I haven't been able to find anything on here about somebody putting one into a 67-72.

They fit just like any other big block.

[meatwagon83]

i find this interesting, i wonder if i could get better mileage out of one of these than my 454? looks like an easy swap with minimum headaches

[DirtyLarry]

Like RatRod68 said, the L18 footprint is just like any other old big block which means for a 67-72 4x4 the engine may need to be moved forward for firewall clearance. One saving grace on the L18 is the fact it does not have a distributor and the early L18’s with EGR valves at the rear of the engine can be removed like the later L18’s to save the firewall room. Without a dizzy or EGR valve the L18 might just fit in there with no mods if the valve cover and coil packs fit under the brake booster. Maybe you can be the first to let us know . I get a lot of inquires on L18 swaps, but never really see any getting done. Lots of talk on the forums but no action

The L18 oil pan will interfere with the original engine cross member where an ORD HD engine crossmember would fix that. You can even use older big block exhaust manifolds/headers on the L18. If running A/C, I recommend using 2001/2002 G-van accessory brackets to move the A/C compressor up to the top to prevent the need to hack the frame like so many other L18 and small block LS swappers have crudely done.

Meatwagon83,

It is an easy swap and much easier than a LS swap IMHO with greater rewards in the end. You could potentially gain more MPG with a L18 over a 454 depending what 454 you have. There is no doubt about it that a L18 will double your fuel mileage from a carbureted 454. I went from a carb’d 454 HO to the L18 and went from 5/6 MPG to 11/12 MPG with gobs more torque and horsepower. The OD trans also helped with the MPG. If looking for MPG increase alone, I don’t think an L18 swap would really be the answer though. Outside of the L18 acquisition cost, you are still looking at $1500 - $2500 just for installation components (wiring harness, ECM tuning, new accessories, exhaust work, etc). A lot of people use old donor harness from the truck the engine came from, I don’t recommend that. A new harness is the best $700 you can throw at a late model engine swap.

[K20chevy]

the 6.0 are bad on gas and maybe a little weak, but the 6.2 is a monster! And way better on gas with the variable valve timing. Sure it is not a cheap swap, bit id you stick with the 6 speed auto that comes behind it, it is almost a bolt in. I went with a ZF S6-650 6 speed manual behind mine, which was ore work to get the righ flywheel clutch combo and get the ECU programmed for the manual with keeping ´08 emissions and the VVT working. Nothing that can´t be done. I had to do the same as Larry, use and ORD crossmember and space the engine mounts up a little with plate, but the truck pan clears well now. The exhaust was a no brainer, I had to build one anyways, so that was no extra cost for me. I´m not running A/C yet, but I´ve see a belt/bracket setup somewhere where you can actually mount the A/C compressor up top on the passenger side. If I ever hook up an A/C, that´s what I´ll do.

Powerwise there is nothing besides a Diesel (not a fan of those) that outpowers that L92 VVT. And the millage totally surprised me... with an empty truck on 4" lift, 35" tires, with winch, etc.. if I stay below 70 on the highway, I can get to 15 mpg! That is pretty good for about 450 HP! with less agressive tires, it might be even better.

So yes, the LS swap might be more expensive, but I love the light weight of the aluminum smallblock and the power to millage ratio is amazing!

And it looks at home and runs perfect in the 78 K20 too....

[K10Scottsdale78]

thats badass!

[DirtyLarry]

The aluminum block L92 6.2L light truck engines are really nice performing horsepower engines albeit I feel they are more suited for swapping into a 2wd hotrod/cruiser truck. Usable HP and Torque doesn’t come on until way too late (high RPM) for my needs.

It would be interesting to drive a sportscar-like 6.2L behind a dump truck S6-650 transmission in a heavy 4x4. As I mentioned in a different thread, I have the S6-650 in my daily driver 8.1L Silverado and hate that transmission. I’ve hated it since the day I brought it home when the truck was new. If it wasn’t for the low RPM torque of the big block that allows skip shifting from 2nd to 4th to 6th I think that clunky shifting thing would really drive my crazy.

Originally Posted by K20chevy

Powerwise there is nothing besides a Diesel (not a fan of those) that outpowers that L92 VVT.

What? Sure there is…it is called an L18 8.1L. To date, there is no other modern day production gasoline engine that comes closer to diesel like torque than a L18. As much as I like the Gen III LS engines the one thing I don’t like is how one must beat on them like a weed whacker to get any usable torque and horsepower out of them. HP is fun, but low-end Torque is what gets the job done in these big 4x4’s. LS engines just don’t have enough low end grunt to work well for what I do with my K10, especially at our altitude here (5,000 ft). The truck weighs 8,000lbs with the camper fully loaded for a week in the back country. Most of its time is spent wondering around the back country of the Southwest where the 8.1L has enough low end grunt that it can be idled along in 3rd gear (NV4500). On the other hand a Gen III LS engine would need to be spun to 2,500 to 3,000 to do the same work while consuming more fuel along the way. I tend to drive my 8.1L’s like diesels where I shift at a very low RPM and the engine seldom goes above 2,500 unless I am on the Interstate cruising along 75+ MPH. It seems LS engines can’t pull away from a stop sign without spinning up to at least 2,500 RPM.

There are actually 4 different HP and Torque SAE ratings of the L18 8.1L depending on the vehicle and GVWR. There isn’t any engine hardware differences between any of these engines, the power levels are all in the ECM calibrations. As with pretty much all GM engines the HP and Torque ratings are very conservative due to emissions. It doesn’t take much ECM tuning by someone that know what they are doing to significantly increase the HP and torque of these things. Like your 450 HP claim on a L92 that is actually rated at 380 HP, the tuner that programmed my ECM also claims some crazy HP and Torque number increases with their “Hot Tune”. Howell claimed 425 HP / 550 lb ft of torque is what their tune was dyno’d at. I’ll have to take their word for it as it is unlikely my truck will ever get on a dyno but I know it moves an 8,000lb rolling box with not much effort

Horsepower ratings of the L18 8.1L:
340 @ 4200 rpm (L18 Workhorse)
325 @ 4000 rpm (MD L18 w/LRW power option)
295 @ 3600 rpm (MD L18 w/LRZ power option)
225 @ 3600 rpm (MD L18 w/LQR power option)

Torque (lb-ft):
455 @ 3200 rpm (L18 Workhorse)
450 @ 2800 rpm (MD L18 w/LRW power option)
440 @ 3200 rpm (MD L18 w/LRZ power option)
350 @ 1200 rpm (MD L18 w/LQR power option)

L92 6.2L:
380 HP @ 5500 RPM
417 LB. FT @ 4400 RPM


The numbers don’t lie, the Gen III L92 LS engine must be beat on to get power out of them. The peak 380 HP rating doesn't appear until 5,500 RPM! Hell, a big block (as well as a diesel) is liable to leave 8 big dents in the hood if it was spun that high very often. LS engines are almost like modern day Mazda rotary engines where you have to wind them up like a weed whacker (although not nearly as bad as a Ford engine).




This is the HP and Torque chart for the most common light truck and SUV L18...the 325 HP version. Notice its Peak HP is 1,300 RPM lower than the L92 6.2L. Notice it is also already building over 400 lbs of torque at 1,000 RPM. They actually make over 100 lbs of torque at idle (750 RPM). Look back above, the L92 is only producing 270ish lbs of torque at 1,000 RPMs. Now which engine is more diesel-like? I still like LS engines alot, just not in a heavy 4x4 or something that will do much towing. There is no replacement for displacement.

[K20chevy]

Hi Larry, my comments and link to video is in red between what you wrote.

Originally Posted by DirtyLarry

The aluminum block L92 6.2L light truck engines are really nice performing horsepower engines albeit I feel they are more suited for swapping into a 2wd hotrod/cruiser truck. Usable HP and Torque doesn’t come on until way too late (high RPM) for my needs.

That is true for the non VVT engines, however mine has 90% of the torqu from 2000 to 4500 RPM. sure it redlines at 6000 RPM, so i revs way higher and the big block sure has more low end torque, but the L92 is way better than the 6.0 that most people use to swap in.

It would be interesting to drive a sportscar-like 6.2L behind a dump truck S6-650 transmission in a heavy 4x4. As I mentioned in a different thread, I have the S6-650 in my daily driver 8.1L Silverado and hate that transmission. I’ve hated it since the day I brought it home when the truck was new. If it wasn’t for the low RPM torque of the big block that allows skip shifting from 2nd to 4th to 6th I think that clunky shifting thing would really drive my crazy.

see video on how nice it shifts and drives



As I mentioned before in the other thread, my S6 650 shifts as smooth as can be and matches the L92 perfect. It´s a blast to drive and people that drove with me were surprised on how well that combo works and shifts.


What? Sure there is…it is called an L18 8.1L. To date, there is no other modern day production gasoline engine that comes closer to diesel like torque than a L18. As much as I like the Gen III LS engines the one thing I don’t like is how one must beat on them like a weed whacker to get any usable torque and horsepower out of them. HP is fun, but low-end Torque is what gets the job done in these big 4x4’s. LS engines just don’t have enough low end grunt to work well for what I do with my K10, especially at our altitude here (5,000 ft). The truck weighs 8,000lbs with the camper fully loaded for a week in the back country. Most of its time is spent wondering around the back country of the Southwest where the 8.1L has enough low end grunt that it can be idled along in 3rd gear (NV4500). On the other hand a Gen III LS engine would need to be spun to 2,500 to 3,000 to do the same work while consuming more fuel along the way. I tend to drive my 8.1L’s like diesels where I shift at a very low RPM and the engine seldom goes above 2,500 unless I am on the Interstate cruising along 75+ MPH. It seems LS engines can’t pull away from a stop sign without spinning up to at least 2,500 RPM.

There are actually 4 different HP and Torque SAE ratings of the L18 8.1L depending on the vehicle and GVWR. There isn’t any engine hardware differences between any of these engines, the power levels are all in the ECM calibrations. As with pretty much all GM engines the HP and Torque ratings are very conservative due to emissions. It doesn’t take much ECM tuning by someone that know what they are doing to significantly increase the HP and torque of these things. Like your 450 HP claim on a L92 that is actually rated at 380 HP, the tuner that programmed my ECM also claims some crazy HP and Torque number increases with their “Hot Tune”. Howell claimed 425 HP / 550 lb ft of torque is what their tune was dyno’d at. I’ll have to take their word for it as it is unlikely my truck will ever get on a dyno but I know it moves an 8,000lb rolling box with not much effort

Horsepower ratings of the L18 8.1L:
340 @ 4200 rpm (L18 Workhorse)
325 @ 4000 rpm (MD L18 w/LRW power option)
295 @ 3600 rpm (MD L18 w/LRZ power option)
225 @ 3600 rpm (MD L18 w/LQR power option)

Torque (lb-ft):
455 @ 3200 rpm (L18 Workhorse)
450 @ 2800 rpm (MD L18 w/LRW power option)
440 @ 3200 rpm (MD L18 w/LRZ power option)
350 @ 1200 rpm (MD L18 w/LQR power option)

L92 6.2L:
380 HP @ 5500 RPM
417 LB. FT @ 4400 RPM

that is not entirely correct. the 380 HP rating is for the regular truck and H2, but the cadillac version had 403 HP from the factory. I got mine from GM performance parts and had it retuned, so the 450 HP is very well possible, even though I haven´t dynoed my truck either.

Applications: Horsepower: hp ( kw )
Cadillac Escalade 403hp ( 301kw ) @ 5700 rpm
Cadillac Escalade ESV 403hp ( 301kw ) @ 5700 rpm
Cadillac Escalade EXT 403hp ( 301kw ) @ 5700 rpm
GMC Sierra Denali 403hp ( 301kw ) @ 5700 rpm
GMC Yukon Denali 380hp ( 283kw ) @ 5500 rpm
GMC Yukon XL Denali 380hp ( 283kw ) @ 5500 rpm

Applications: Torque: lb-ft ( Nm )
Cadillac Escalade 417lb-ft ( 565Nm ) @ 4300 rpm
Cadillac Escalade ESV 417lb-ft ( 565Nm ) @ 4300 rpm
Cadillac Escalade EXT 417lb-ft ( 565Nm ) @ 4300 rpm
GMC Sierra Denali 417lb-ft ( 565Nm ) @ 4300 rpm
GMC Yukon Denali 417lb-ft ( 565Nm ) @ 4400 rpm
GMC Yukon XL Denali 417lb-ft ( 565Nm ) @ 4400 rpm






The numbers don’t lie, the Gen III L92 LS engine must be beat on to get power out of them. The peak 380 HP rating doesn't appear until 5,500 RPM! Hell, a big block (as well as a diesel) is liable to leave 8 big dents in the hood if it was spun that high very often. LS engines are almost like modern day Mazda rotary engines where you have to wind them up like a weed whacker (although not nearly as bad as a Ford engine).




This is the HP and Torque chart for the most common light truck and SUV L18...the 325 HP version. Notice its Peak HP is 1,300 RPM lower than the L92 6.2L. Notice it is also already building over 400 lbs of torque at 1,000 RPM. They actually make over 100 lbs of torque at idle (750 RPM). Look back above, the L92 is only producing 270ish lbs of torque at 1,000 RPMs 320 on the stock one mine is based on. see the dyno chart above.. and that is before the tune. . Now which engine is more diesel-like? I still like LS engines alot, just not in a heavy 4x4 or something that will do much towing. There is no replacement for displacement.
[IMG] http://farm4.staticflickr.com

A lot depends on gearing too. I have 4.88 gears, so that thing moves like a sports car from a stand still.

/3828/11901401666_61e791a429_c.jpg[/IMG]

[K20chevy]

Originally Posted by K10Scottsdale78

thats badass!

Thanks!