Diesel engine swap
 

Can you guys tell me what are the best candidates for diesel swap into these trucks and burbs without too much hassle? I have done LS swaps 3 times now and I want to figure out diesel options for my suburban to give it new life and use it for towing more often. I see the 6BT cummins selling for well over 3 grand with high miles and no accessories on ebay. I'm hoping to find a combination that gets me some engine and compatible transmission for under 3k. My LS donors cost me 1600 at the MOST with transmission and accessories. I have pretty much the normal amount of tools required to fab and modify as needed for exhaust, wiring, etc. but I want to keep from cutting up the stock firewall and frame. Is there some oddball combo you might have seen like an international engine or forklift as a donor? haha I'm just not knowledgeable of the diesel world and what I could use that would be low maintenance and simple to repair when needed. I was looking at the 80s gm 6.2 diesel engine as well that came in these back then. I have never seen one in person or known anyone with one. Maybe the later model GM 6.5 or 6.6 from the 90s and 2000s?

Re: Diesel engine swap
 

If what you want is a reliable tow machine get a 2500 HD parts truck with a 6.0L LQ4. 300 hp at 4400 RPM and 360 ft-lb at 4000 RPM and it comes with a 4L80E that'll fit under the transmission tunnel. My 2005 tows just fine. Yes it only gets 13mpg and 11 towing. That's noticeably better MPG, HP, and torque than a carbureted or TBI 454 and I'd have to run an awful lot of tanks of fuel through at 18mpg to pay for a dirtymax.


Diesels are trendy so the prices are outrageous.
Cummins engines cost a pretty penny.
The 6.2 & 6.5L Detroit AMG Diesel engines are a minimum of 20 years old now. The dirtymax is newer but any half decent dirtymax truck is going to be more coin than a decently running LQ4 equipped 2500HD.

Re: Diesel engine swap
 

Hassle is an ambiguous term.

You didn't mention what trans. You will need an overdrive if you want any economy at all.

6.2/6.5 will bolt in...literally. But you have engine age, and the 6.5 turbo setup won't fit with factory heater box in the engine compartment. Parts are getting harder to find, but they are out there. Avoid the electronically controlled engines.

Duramax (6.6) you can find engine mounts now from several sources. You need to be good at wiring or spend $$$ on a stand-alone harness. Used engines are coming down in price, but you are still going to spend 4-5-6K on just an engine.

Cummins. Big, heavy, can find bolt-in mounts. Easy to wire. Need to adapt GM to Dodge for accessories, etc... Look in the diesel conversion sub forum and you will find several of these. This will probably take the most fabrication.

That being said, I stuffed a 6.5 turbo into my Jeep Grand Wagoneer and have it built into a 275hp/550tq piece. Backed by a 700R4 that was built on a K case and has every possible upgrade installed. If I had to do it again, it would get a 4bt because of what it just cost to build a new 6.5 for it.

And my 87 R30 (currently 454) is going to see a Cummins some day.

One thing you didn't tell us was how you intend to use the truck? Heavy duty tow rig, well then Cummins or Duramax or get really cool and use an International DT360. If you have a half ton that you want to cruise around with and do some light duty towing, then stuff in a Cummins 4bt.

Re: Diesel engine swap
 

I just read some more information and I will have to study up on these. If they can be swapped in and the electronics can be simplified like my LS swaps then it could be a good option for me.

Re: Diesel engine swap
 

The LQ4 is a bulletproof Gen III engine, 130,000 ish mile parts trucks with it in the engine bay are fairly inexpensive, and it makes a fair amount of power in stock dress. The 4L80E in these rigs is a known reliable quantity as well. That's why I suggested it.

The 6L80 sounds nice til you add in the fact that you're locked into a more expensive Gen IV engine with VVT and the fact that the 6L80 doesn't have a 30 year reliability track record like the 4L80E. The GMT900 and K2 parts trucks are going to cost significantly more than a GMT800 C or K 2500 or 3500 with the LQ4/4L80E.

AFM is a known problem child. VVT might, or might not, be a problem. More parts in the valve train generally isn't a recipe for longevity.

If you have a 4x4 the NP208C & NP241C will bolt up to the 4L80 or 6L80 with a clocking ring to re-set the drop. The NP205 or NP203 will be a bit more involved but not terrible...

Re: Diesel engine swap
 

np205 and 6l90e or a 6l80e is pretty easy adapter isnt expensive. you do need to add vss signal pretty easy to do. the 4l80e will also requires a spacer and the vss mod. personally owning both id rather have the 6l90 over all of them. i loved the power and gearing of my 07 truck that had them. if the thing hadnt been thirsty and super prone to rust id still own it. 6.0 vvt with 6l90e is a super strong set up and really powerful. in a lighter truck than my 07 cc lb 4x4 it prob would get pretty good mpg. 6500k weight or more is alot to move around. it got 12 mpg still. now the 5.3 thats in front of a 6l80e is another story. the afm is the issue with them. delete that and its a excellent engine also. keep it you are asking for lifter issues. you want to keep the vvt its solid and really makes the truck wake up. as for diesel only engine id have is a cummins if i was going to do a swap. but in a half ton burban thats overkill imo. you arent going to be pulling 16k behind it.

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Re: Diesel engine swap
 

Re: Diesel engine swap
 

Seriously, if you are looking for 350ft/lbs of torque, why are you looking at diesels? Those are stock 6.2 non-turbo numbers. The 3 liter diesel in my BMW makes well over 400. You are really looking at 4bt numbers, and you can back it with a 700R4, 4L60E/4L80E (if you want to deal with electronics), or any 5 speed manual.

6.0 gasser will easily surpass those HP/TQ numbers and be a fairly easy drivetrain swap. From having done a diesel swap myself, there are A LOT of little things that come with changing from gas to diesel. As much of a fan as I am of diesels, I agree with Hatzie on this one that you should take a serious look at the 6.0 gasser.

Towing 10K lbs on a 1/2 Burb chassis? You might want to rethink that. That 1/2 ton running gear also won't live long behind anything larger than a 4bt. A Dmax/6bt/DT360 will blow the ring and pinion out of that rear end the first time you nail the throttle. I had to upgrade my Jeep to a 14bolt for that reason.

Re: Diesel engine swap
 

They say the higher gear ring and pinion are actually stronger than the low gear since it has the larger pinion but I do see your point.
I have abused my trucks 2.73 axle and it has actually never given me any problems which is amazing when I think about it.

Re: Diesel engine swap
 

I'm not having much luck finding 5.3 or 6.0 gm engines so far. I see them for 5k and up and they are not decent pullouts. Accessories missing, clearly sitting outside for who knows how long, no wiring or computer, some shady looking. Might need to try and pick and pull myself to get a decent and complete setup.

Re: Diesel engine swap
 

Funny how different parts of the country have different availability.

You need to look North in the snow and salt states. You can get some pretty decent running drivelines in completely rotted out body and chassis. I bet you only need to look a few hours North in Missouri or Iowa for similar complete Swiss cheese vehicles. You'll need to trailer em home but that's not a big deal for what you get.
I never buy engines I can't hear running and run tests on to evaluate the condition. You can run a pretty decent dynamic compression test with a scope. If the seller doesn't want you to plug in with a diag tool you walk away.

Re: Diesel engine swap
 

Local late model junk yard had so many LSs and no turn around, they loaded up 2-3 40' dump trailer and scrapped them. Pissed a lot of people off. Could have sold them for couple hundred each to the public. But there is a pick a part right next door that has them as well, couple hundred for a complete motor. It's funny, people talk about gas mileage with these, and they don't get any better than the Vortec 454 I had, and wouldn't out pull it either....Me? Not sold on LS's.

Re: Diesel engine swap
 

The fact that they wouldn't sell em to the public has more to do with Tioga, Broome, Chemung, Chenango, Otsego, and Delaware county politics mixed with the NYC moonbat driven BS from the Assembly, Senate, and Governors office in Albany. Every time I see this BS I think how glad I am that I left the area 37 years ago.
Combine that with the bizarre Carnie mentality you see in flea market sellers and junk car outfits. They'll get pennies on the dollar or nothing at all by scrapping them or pitching them in a dumpster rather than sell them for less than they think they're worth.

The 6.0 has more HP and Torque than a stock carbureted 454. Around the same power numbers as a GMT400 with a 454 TBI... Significantly more HP and slightly lower torque to the 6.0L LQ4 compared to the 454 TBI. The 6.0L LQ4 definitely gets better fuel mileage than a square or GMT400 with the 454.
My best mileage in my 86 K20 with a 454 and 700R4 was 9.5mpg on the highway. I get right around 14 with the 6.0L K2500HD. The 2500HD is a heavier chassis with the same gearing as the old K20 squarebody.
My best in-town with that 454 K20 was 7mpg. The 6.0 gets just shy of 12mpg but as low as 11.

The numbers on the VVT version of the 6.0L truck motor in the GMT900 and newer rigs moves significantly in the favor of the 6.0L over the old inefficient 454.

The 325ci 5.3L has more power on tap than the 350 smallblock. The 4.8L LS V8 has better numbers as well. Even in the heavy GMT800 & GMT900 chassis they pull fairly well.

The electrical and mechanical engineers beat the bean counters on the LS.

Re: Diesel engine swap
 

TBI maybe not Vortec. 290 horse 410 torque. Friend towed with both, 454 pulled better maybe same mileage not towing. But towing got better with the 454, and it pulled better, and not bouncing the tach off redline. Now this is with 4l80s. So it prolly be better with the 6 or 8l90.

That junkyard does some stupid stuff. Want top dollar for used parts. Can get new for couple bucks more. Prolly junked the motors so wouldn't have to deal with the public. Many guys are using the motor for test pigs for turbo's nitrous whatever. Now they just go next door and get a complete unit for less. Their loss. Other than late model parts, another reason I don't go there....

Re: Diesel engine swap
 

The LY6 is 365HP and 383ft-lbs.
If you dump a cam in it you easily move it into the 440 hp and 460 torque range. This outstrips the 454 Vortec for a less money and you get the 6L80 with 6 gears or the 8L90 with 8 so the fuel mileage is far better.

The time of the old iron block smallblock and big block GM engines for daily drivers has come and gone for the most part.
They are antiques and worth restoring if that's what you want. If you want a reliable daily you want an LS.

Really bizarre behaviour on the part of a business that's purporting to make money. It wouldn't be shocking to find out they're getting cash infusions from IBM (Italian Businessmen) in Philly, Jersey, Utica-Rome, Albany, or Brooklyn.

Re: Diesel engine swap
 

can do the same to the 454 and still get more out of it. Ever look at drag cars, pulling trucks, monster trucks whatever? They all have big blocks. I'm old school. I like big blocks, but since can't afford one right now, I'm going small block. But to each their own, build what you want. But IMO an LS is not the end all be all.

I should have stayed out of NY when I had the chance. But got tired of missing out on friends and family. Now pretty much stuck, G/F has a good job, and I have a good job with the state, ironic lol....

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I agree with a lot of that. I have both, a GMT400 with a vortec 454 and a GMT900 with a 6.0(L96 w/VVT). Both trucks have 3.73 gears. The 99 weighs 6800 with me in it, the 2011 weighs 7500. They tow my 8,000 pound trailer about the same(only different). The 454 has more torque, and the torque starts at low rpm, and the curve is relatively flat. I put the shifter in 3 like the owner’s manual says. The 6.0 is a great motor, but not as good as the 454 in my opinion. The only thing that saves it is the 6 speed transmission. The first gear is so low it acts like a granny. It lets the 6.0 rev up where peak hp/tq are. The 454 gets 11 mpg, 9 when towing. The 6.0 gets 13, but it drops to 6.5 when towing. The 6.0 is a lot more refined. I can have a conversation with my passengers without yelling. I can’t say that about my 99. And to clarify, I am comparing a stock motor to a stock motor.

Re: Diesel engine swap
 

LOL I love the comparisons on non-stock LS's performing better than a stock 454. Take the money that you would spend on a LS swap and put a fraction of it into a 454 and it will outperform a built LS all day when towing. And you don't have to run the 454 at 4000rpm to make the power.

How do you get that a LS swap + cam is less money than just sticking a cam and a tune on a 454?

Re: Diesel engine swap
 

To push the 454 to those numbers takes more than a camshaft and tune.
Pistons, Carburetor, Intake, Headers, Exhaust, Ignition recurve.
Tweaking the EEPROM TBI 454 is more than a little bit involved. I used one of the original Ostrich flash tuners to refine EEPROM programs before burning them to a chip when I was playing with TPI... Not something I'd look forward to repeating now.
A well loved 454 with flash chips in the PCM will cost you a fair chunk of coin around here. It's almost cheaper to buy a Cummins from the salvage carnies.

You can reach those power numbers with an LQ4 using the GM LQ9 camshaft and tweaking the PCM. No exhaust, pistons, ... needed. You'll get more with an exhaust and other mods but a Cam and tune will put you comfortably in the mid 400's

As for the price of entry here in rust country... buy a rusted out donor truck so you don't get raped by the junk carnies.
I paid $350 for a good running 2003 2500HD rust bucket LQ4 4L80E NV263 donor chassis with 163,000 on the clock. The frame, bed, and cab were Swiss cheese. I drove it home from Vermont at a nice slow speed praying the entire trip.
I sold the interior, NV263, front axle, and various other parts for more than I paid for the whole truck. My brother installed the engine and transmission in his 1986 K20 and I cabbaged a few parts for my 2005. My kid brothers' engine donor made me money even tho he paid me nothing for it.
We're eyeballing the 10.5" AAM 14bolt with disc brakes to replace the 9.5" 14bolt in the same truck.

Re: Diesel engine swap
 

A THROTTLE BODY yes, it were not talking about those. I had 2, and they ran pretty good. But knew the power was limited. I had an engine builder tell me you could stick a flower pot in a cylinder or a big block n still make power.

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Unless you are going with a carb, forget about trying to make decent power out of a 454 North of 350hp....the fuel injection (stock stuff) just cant support it. An 8.1 can make around 350-400hp and be tuned really easily (same as LS), but North of those numbers you are talking BIG $'s to swap out better internals in the engine.

As far as pulling comfort.... all of these big blocks in stock trim will pull about as well as a 6.0, but they won't be screaming in 2nd gear on every little hill.

Depending on how often you will be pulling heavy, I would lean towards the LS 5.3/6.0 if its only a few times per year. If you plan on every weekend, I would be hunting an 8.1 or Cummins.

Re: Diesel engine swap
 

4bt is but i think you need a bread truck transmission adapter. still its slow and the mpg gain really doesnt help much on diesel with the added cost of fuel and upkeep an 4bt and new turbo is alot of money vs a ls engine. the 5.3 and the 6.2 has afm. the 6.0 and 4.8 did not ever have it. the 4.8 only had a 4l60e behind it ever and didnt have vvt. the 6.0 after or 07 in the newer body style had vvt and the 6l90e behind it. vvt really wakes them up. it gives the engine plenty of low end then the vvt adjust the timing to give it top end. its not like a honda setup it just adjust the cam profile and timing. you can delete afm on 5.3 pretty easy too. just requires a few hundred bucks and tuning. now this is the truck engines i think some cars that had 6.0s had afm never fooled with them. i know the police cars didnt but idk about gtos g6s etc...

Re: Diesel engine swap
 

as for a 454 vs a 6.0 a ly6 makes alot more power in stock form and torque numbers is 30lbs less. ly6 with a cam gains 75 hp 75 tq just from a cam swap and still can been street mannered like its bone stock. thats a vortec one from 99. i dont see a carb one making that without a serious cam headwork intake and so forth. by the time you spend that kind of money you can stroke a ly6 to a 408 and cam it. 408 would not be touched by a 454 unless it was a full build talking aluminum heads cam intake all that. parts for a ls are cheap. we aint even talking about the fuel to feed this. ly6 isnt great on mpg but not terrible and get really no worse with a cam and tune but a 454 built like that is going to a be a very thirsty girl.

Re: Diesel engine swap
 

DynamicEFI make the stock ECU laptop tunable with WB O2 support. A set of stock L29 heads, 214 degree cam, intake and my torque is over 500, and I'm over 450 as low as 2000rpm. 6.0 can't touch that for towing. I have way less into this combination than a LS swap.

Re: Diesel engine swap
 

Donor vehicle cost differs depending on the area of the country. You're generalizing vehicle conditions in your area to the entire country the same way you desert folks assume that water is surely a scarce commodity everywhere. Not all of us live in the desert. I can dig a twenty five foot deep hole in the meadow behind my house and I'll have a well with drinking water that doesn't run dry.

A twenty year old GMT800 truck is plenty serviceable in the rust and salt free Southwest so they are in daily service and command a price based on the fact that they are a serviceable vehicle for daily use.
However... here in the salt belt they're rusting out and entering the salvage market in increasing numbers. They are great cheap LS engine donors.

The CK, RV, & GMT400 trucks with 454 engines in the salt belt rusted out and were removed from daily use long enough ago that the remaining available rigs and parts now demand a premium price in comparison to the newer GMT800 and even GMT900 rust buckets that are being retired.

Re: Diesel engine swap
 

Please price out a LS swap and modifications that will generate the HP/torque numbers that I'm pulling. I have about $1200 into everything, and that was because I had the heads redone and added new valves.

I'll say it again - you cannot LS swap and build to 454 power for less money than some simple 454 mods.

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We had 6.0s in the dump trucks at work 3500 8ft body and they were dogs even the v10 in the brand new f550 feels gutless with a load in it I’d like to drive the new 7.3 Ford and see how that is but we haven’t gotten one yet.

Re: Diesel engine swap
 

What kind of gas mileage out of this setup not towing just unloaded.? I have a similar dually but with a 400 trans, no overdrive. Figuring its impossible to get better than 10mpg.

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If you already have a reasonably serviceable engine and you buy Chinese parts you can probably do it for $1,500... how long is it going to last running Chinese floor sweepings inside?

Mid 90's rebuildable running 454 cores are right around a grand. Decent quality parts to build em are quite a bit more than $1,200.

The 454 is a pig. I've never run better than 10mpg unloaded with a 454 and best towing was around 8.5mpg. Might as well get an 8.1L Vortec. Similar MPG and more power.

Re: Diesel engine swap
 

What chinese parts? You are going way out in left field to try to convince yourself that the LS will compare with the 454. There is nothing Chinese that I have put in my engine. Factory GM heads, Clay Smith cam/lifters. My dually now gets better than 12 (better than 13 on the highway) with these mods and the overdrive. There is no way you can swap in a LS and make the same power as a 454 without spending a ton more money. I'm not saying LS is a better or worse engine, you just need to get out of the fantasy that building and swapping a LS is somehow more economical than just modding an existing 454.

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Best change was adding the overdrive. When I had the TH400 I averaged right at 9 in just regular driving. With the NV4500, I got 11 consistently. With the update to the heads and cam, I get high 12's consistently driving around town and high 13's on road trips. I was getting 6-7 with our travel trailer and now I can flirt with 10 if I take it easy. I use overdrive a lot when towing.

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That's because LSs are a cult. I asked a shop well known for big power LS builds if it would be cheaper building a big block or an LS. The only condition I had was 500lb-ft at 2500rpm. He told me there was no possible way to get a big block to do that without going to all expensive forged parts, and that an LS was the only way to go. He then showed me a build they did recently that almost made that torque, for $17,000. Meanwhile I can buy a 502 from GM for $8500. Only a cult member would come up with something crazy like that. I don't care how good the mileage is, $8500 buys a lot of gas and the 502 will do it on 87.

LSs have their place, but low end torque isn't it.

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You can do that with peanut port heads. The 454SS guys get crazy numbers with those little heads.

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I think a 6.0 vs 454 is a good matchup. The 454 needs to to be bigger since the 6.0 is a newer and more efficient powerplant. Sure, the wildest drag setups are usually 572s, but give that another 15 years. Or maybe not. BBC is awesome so long as you don't fret your fuel mileage.

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Since we're on the topic, I'll chime in with real world experience here. Had an 09 3500 GMC with 6.0 automatic and 4.10s. Biggest disappointment I've ever had, towed crappy, wouldn't make any hill without SCREAMING high RPMs, and I NEVER saw anything over 11 MPG.

Best buddy has a crew cab square dually. Newer GM crate 454, TH400, 4.10s or 4.11s. Will tow circles around the LS truck I had, rarely downshifts, and averages.... Yep! About 11 MPG. I'll take the BB any given day. The 6.0 is IMO the most disappointing engine for a tow rig that ever there was. The low end torque just isn't there.

There is still NO replacement for displacement. Big HP numbers are impressive, but are derived from torque and RPM. Torque is the variable that gets things moving

Re: Diesel engine swap
 

The cult of the Big Block exists as well.

There's also the cult of the diesel and more specifically the cult of Cummins.

11mpg is more than a little optimistic on the 454 and fairly pessimistic on the 6.0L. My average on the 6.0L is 12.5mpg over the last 2 years.
The 6.0L LQ4 swap on my brothers' truck cost right around $600 for the plugs & wires, motor mounts, water pump, oil pump & pickup, fluids, and recently the $259 GMPP LQ9 cam. The engine and transmission was essentially free before the repair parts, camshaft, and motor mounts. It's a non AC truck so the AC compressor went away... if you want AC it'll cost ya.
It was a lot of work to re-purpose the GMT800 harness & PCM as a stand alone setup and the motor mounts were not drop-in parts either. I did have a complete running rust bucket as a donor if you're buying from a salvage yard you're going to get raped with no lube.

You have to weigh a bunch of factors. Location enters into the equation as well.

Want's...
-If you're towing all the time you're better off to get a diesel. The maintenance cost is higher than gasoline and the cost of a donor engine or truck is plenty high as well.
-The 454 or 8.1L Vortec are a second best for full time towing but the fuel mileage is pretty scary. The 8.1L is pretty pricey and the 454 is old enough now that you will be unlikely to find a reasonably priced un-molested core to rebuild. Rebuild parts that aren't from China will cost you as well... despite what the cult of the big block tells you.
-My 6.0L is much more to my liking than the big blocks and diesels I've owned for the occasional towing I do. Maintenance is fairly low and it gets decent fuel mileage. Mileage is not as good as a diesel and not as bad as a big block. It's roughly on par with my 305 & 350 smallblocks over the years. You'll pay a fairly healthy price for any LS truck in the salt free desert states, non-coastal South, and Pacific Northwest. You're competing with salvage yards and flippers for wrecks in the salt free states. You can find rust bucket donors fairly cheap in the salt states.

None of the three are remotely affordable if you're stuck with crate engines or bending over and grabbing your ankles for the junkyard goons.

Modifying engines for performance costs you reliability and lifespan. That's the way it is. Some mild mods are less detrimental but they do cost you on lifespan.

I have an 86 K20 to work with right now. 350-SM465-NP208-10bolt front-9.5" 14bolt rear. It needs a new engine. I'll rebuild the original 350 smallblock and run it with a rebuilt Rochester Quadrajet, cast iron intake, mechanical fuel pump, cast iron manifolds, and stock HEI. I am replacing the beat up 10 bolt with a rebuilt Dana44 and the burnt up 9.5" 14bolt with an already rebuilt 10.5" 14bolt. Probably pretty boring for you guys but it'll still be running well 150,000 miles after I'm done with the re-build.

Re: Diesel engine swap
 

Sure.

Any time LSs are brought up, it's said that they 1. make more power, 2. get better mileage, 3. are cheaper, and 4. are more reliable. They're always one of those things, no matter what. With a little effort they can be two of those things. Given the right circumstances they can be three. And yet the cult members will always claim all four to be simultaneously true in every instance.

I don't know why people join the LS cult. They have their place, and they're great at what they do. But they're not the answer for everything like the cult would have you believe.

Making up stories about BBCs requiring Chinese parts to compete with LSs sounds like something a cult member would say.

I personally wouldn't put an LS in anything that didn't come with one because I hate the sound of them. I suppose I'm a member of the anticult.

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You're blowing smoke up our asses with your $1,200 comment. At the $1,200 price you were quoting for internals and machine work you're using Chinese parts. No way around that. Hence my comment about the cult of the big block.

Bore and hone, ground crank, align bore the mains, cleaning up the rods, three angle valve job, threaded rockers, valve guides, douching out in the hot spray, ... you're near a grand right there.
Forged pistons, Quality rings, Clevite bearings, Fel-Pro gaskets, quality camshaft, quality lifters, and other quality internals along with all the other little bits n pieces like freeze plugs, fuel pump(s), and injection repair or rebuilt carburetors not to mention the parts to re-work the distributor cost real money. You ain't going to buy those pieces for $300.

If you cut corners on a 1960's-1990's Big Block or SmallBlock rework all your hard work doesn't last. Slapping good quality parts into a block without the machine work needed for longevity means you have a worn block that'll run hot n heavy for 5,000-10,000 miles... maybe less and maybe worse than when you started.
Your MKIV & MKV big blocks are 25-50 years old. The MKVI is minimum of 20 years old... with the associated abuse of the years. Finding one that's not abused for a reasonable price is a unicorn.
You can buy a crate 501 for eight to nine grand but that ain't on par with the cost of a used rust bucket LS truck with lots of life left in the driveline and parts to sell aside from the powertrain.
I've sourced rusted out 2000-2004 K1500 trucks with just 100,000 on the clock for $500. The 4.8 & 5.3 do just fine in a grocery getter 1/2 ton truck the 4.8 power levels are on par with a stock 350 smallblock and the 5.3 is better. I've found rotted out 2000-2006 K2500 LQ4 trucks for as low as $300 with 100,000 - 150,000 on the clocks and used the engines for 3/4 & 1 ton trucks. You have to be careful of what you buy but they're easier to find than a good MKIV to MKVI or smallblock donor.

The essentially free LQ4 I used in Mikeys' truck should run another 150,000 maybe more with no issues. He's cranked around 20,000 onto it so far. That used LQ4 had over 100,000 on it so we installed an oil pump and pickup, re-sealed the pan and valve covers, and replaced the water pump for insurance. The leakdown test showed the rings, head gaskets, and valves were sealing properly and it ran nice and smooth. The donor truck frame parted company in two places and I had to cinch it together with binders for its last slow drive from VT to my barn. I sold bits off the truck til it paid for itself before I dragged it to the yard and Pat is still selling various bits off it.
The 4.8 & 5.3L with AFM get torn down and get non AFM lifters & cam installed. This costs money for gaskets and the GMPP cam kits.

If you need stump pulling torque get a Cummins or Dirtymax.
If you want to say you have a diesel get a 6.2 or 6.5L AMG GM diesel.
If you need to tow a lot get a Cummins, Dirtymax, or an 8.1L MKVII Vortec.
If you want bragging rights get a 501 or build a MKIV-MKVI big block.
If you want decent power for some towing and reasonable fuel mileage get an LQ4 with a 4L80 or LY6 with a 6L or 8L.
If you want a reliable engine that makes reasonable power that you don't have to fight with all the time get a 5.3 or 4.8 LS.

Re: Diesel engine swap
 

Try to keep up with the conversation. No one said I rebuilt the engine for $1200.

I had a good existing 100K mile 454 in my truck. Cost of heads, head work, cam/lifters/springs/valves, timing chain, and ECU mods was about $1200.

You cannot swap in an LS and have it make the power that I make for that price. Period. That is why I challenged you to price out an LS swap that makes the same power that I am making. You can't do it.