Potential Build, Destroked Aluminum 5.3 to 4.8, IR Intake, 8500 RPM

[theastronaut]

I'm in the planning stages for an engine for my '66 daily driver/mild pro-touring build. I know little about building LSx engines, though I've worked with hi-po aircooled VW engines for awhile. I've been thinking about building a 4.8 using an aluminum 5.3 block for better mileage, and also the crank would be stronger due to more rod journal overlap. The truck will be used as a daily driver, and run at open track days, and the occassional autocross. I'm not wanting to compete with it, just want to get it out on the track and have fun. I'm planning on using an individual runner intake with four 2 barrel Dellorto or Weber carbs for the intake. I haven't decided whether I'll use downdraft or sidedraft carbs/intake yet. IR intakes broaden the powerband, and tames big cams since they eliminate reversion problems that plenum type intakes have. I'd like it to rev to around 8500 rpm, and make good power to around 7500 rpm. I think the broad powerband that the IR intake offers would be great especially for autocrossing where you're usually stuck in a single gear the whole run.

I have experience with Dellorto carbs on IR intakes; I use them on my daily driver VW. They're extremely driveable and make a ton more average power than plenum manifold systems do. My old stock engine'd VW daily driver went from getting 24 mpg hwy to averaging 32-34 mpg mixed city/highway, with a peak of 36.25 mph hwy, so they're not as radical as they look. I can use MSD for the ignition, use a wideband AFR gauge and tune it myself just like I have with my VW.


Here's what I'm planning so far, let me know what you think! Like I said, no previous experience with LS engines, so I don't know what heads/cam/valvetrain I'd need.

Aluminum block 5.3 (Less weight on nose of truck = better handling)
4.8 crank and rod length.
Forged rods.
Forged Pistons.
IR intake.
Four two barrel Dellorto or Weber carbs.

[BR3W CITY]

Well, I'm pretty sure your the only one hunting for LESS displacement lol. Sounds like a cool idea, I saw a similar setup at LSFest, but it used itb's instead of itc's so you could keep fuel injection (which I prefer, because I'm carb-retarded).

[theastronaut]

Originally Posted by BR3W CITY

Well, I'm pretty sure your the only one hunting for LESS displacement lol. Sounds like a cool idea, I saw a similar setup at LSFest, but it used itb's instead of itc's so you could keep fuel injection (which I prefer, because I'm carb-retarded).

I'm just the opposite, never done anything EFI before, but know how to tune carbs. Well, Dellorto's anyways- I'd be lost on a four barrel!

[BigDan3131]

I think the only problem will be in finding an intake for your Webers. Your not the only one looking for mileage, except I will be swapping the 4.8 into my S10. I will leave it bone stock and just switch to a carb built just for it by either the Carb Shop or SMI.

[theastronaut]

Originally Posted by BigDan3131

I think the only problem will be in finding an intake for your Webers. Your not the only one looking for mileage, except I will be swapping the 4.8 into my S10. I will leave it bone stock and just switch to a carb built just for it by either the Carb Shop or SMI.

You're right about the intake being hard to find. I did find one company offering a billet intake for the IDF/DRLA carbs or TB's, but it was $1600 bucks!! I'll make my own if I have to!


The guy in the link below made his own IR intake from an Edelbrock Pro Flo LS1 intake. He's using throttle bodies instead of carbs, but the manifold would pretty much be the same. I'd have to check and see if the intake runners on the Pro Flo manifold match up pretty well with the Weber IDA or IDF pattern, and choose carbs based on that. Aluminum carb flanges are easy to find and could be welded onto cut down runners of the Pro Flo manifold; assuming the runner spacing is ideal.

http://m.modernhemi.com/forums/showthread.php?t=1269857

[BR3W CITY]

Pantera Stacks (its for injection but pretty cool)
http://panteraefi.com/LS1_STACK_INJECTION.html

There is a 4-6 pg thread on ls1tech about Itb's. Harrop and Ingles were making some kits, but I guess it depends what exactly you want. Some offer a lower that you can setup for either i-tb's or itc, whereas others are a complete manifold including carbs.

[BigDan3131]

Was that 1600 buck manifold a Hogans sheetmetal one by chance?

[theastronaut]

Originally Posted by BigDan3131

Was that 1600 buck manifold a Hogans sheetmetal one by chance?

It was from Extrudabody, $1,650.00.

http://www.extrudabody.com/servlet/t...evy-LS1/Detail




After doing more research, the bore spacing of Weber IDA carbs is 8mm wider than the runner spacing of the Edelbrock Pro Flo intake, so each runner/carb throat would only be off by 4mm. That could easily be fixed when making the carb adapter plates to weld onto the cut-down runners.

The guy in this video is where I found the idea.

Movie LS1 LS2 ITB fabrication from...

[85burb]

The motor is gona need some work if you plan on spinning it that fast. LS1tech has tons of info. The least i can think of is the best arp rod bolts with rod resizing and main studs. I am sure ls1tech.com has all the nessecary parts lists. Just be care full if you post over there with out searching first. Some of them on that site are jerks.

[theastronaut]

Originally Posted by 85burb

The motor is gona need some work if you plan on spinning it that fast. LS1tech has tons of info. The least i can think of is the best arp rod bolts with rod resizing and main studs. I am sure ls1tech.com has all the nessecary parts lists. Just be care full if you post over there with out searching first. Some of them on that site are jerks.

Thanks, I signed up there earlier and made an introduction post but haven't had and replies yet. I kinda saw what you're sayin about the place, they don't seem overly friendly over there. I was planning on running afternarket forged rods, unless the stock ones could be beefed up? I read that LS6 Z06 engines had lightweight hollow valves that would be good for high rpm's. I think GM discontinued them though.
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[85burb]

I am not thinking you could do anything other then bolts to the rods. I would get the best bottom end you can afford. I am not sure if they discontinued the valves or not but tons of people over there on ls1tech get rid of them for some reason. Maybe titanium valves. I like the texas speed and perfomance heads. I will get the 6.0 stage 2.5s one day. They flow good and are dirt cheap and tons of people use them.

[69trk]

Originally Posted by theastronaut

Thanks, I signed up there earlier and made an introduction post but haven't had and replies yet. I kinda saw what you're sayin about the place, they don't seem overly friendly over there. I was planning on running afternarket forged rods, unless the stock ones could be beefed up? I read that LS6 Z06 engines had lightweight hollow valves that would be good for high rpm's. I think GM discontinued them though.
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I signed up over there also and have had no replys on my introduction... I don't think they like old school trucks.... Good luck on your build!!!

[theastronaut]

Originally Posted by 69trk

I signed up over there also and have had no replys on my introduction... I don't think they like old school trucks.... Good luck on your build!!!

They said to let them know what you're into, so I said 64-66 Chevy trucks and early VW bugs, and posted a couple pics of the VW. They prolly didn't like the VW.
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[BR3W CITY]

Originally Posted by theastronaut

They said to let them know what you're into, so I said 64-66 Chevy trucks and early VW bugs, and posted a couple pics of the VW. They prolly didn't like the VW.
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Could have been worse, you could have said that over on Yellow Bullet

[BigDan3131]

Its just fortunate that we have open minded people on here with experience in all things. The only other forums I go to are the Turbo Forums where if you wanted an engineer level answer you can get it there.

[Cannon007]

you should use a 6.0L block so you can use the bigger 4.0" bore and put some better flowing heads on it. This high reving build is more suited to a little light weight car though so IDK how much your truck weights but I would just build a big cube LSX(408 - 454) that revs easily and cheaply to 7000 and call it a day. Oh and ofcourse make it an aluminum block. An FFR cobra replica or GT40 or RCR superlight kit car would be really cool with a build like this though and would sound like an old can am racecar! But I'm guessing you have your heart set on this for your truck so...your going to have a hard time researching this cause its one of those builds that venture off into somewhat rare territory. Good luck

[theastronaut]

Originally Posted by Cannon007

you should use a 6.0L block so you can use the bigger 4.0" bore and put some better flowing heads on it. This high reving build is more suited to a little light weight car though so IDK how much your truck weights but I would just build a big cube LSX(408 - 454) that revs easily and cheaply to 7000 and call it a day. Oh and ofcourse make it an aluminum block. An FFR cobra replica or GT40 or RCR superlight kit car would be really cool with a build like this though and would sound like an old can am racecar! But I'm guessing you have your heart set on this for your truck so...your going to have a hard time researching this cause its one of those builds that venture off into somewhat rare territory. Good luck

It would be 312 CI with a 4.8 crank and boring it to 3.90" (LS1 size), so it would be on the small side. It'll be geared short- 4.56 with a T56 6 speed so 1-4 gears should be pretty short and tightly spaced to get the weight up and going. I'll be doing what I can to reduce the weight of the truck and from what I can find about the original curb weight, I'm hoping to get it down to around 36-3700 so it shouldn't be terribly porky for a fullsize truck. I could always change back to the 5.3 crank and rod length fairly easily if it didn't make enough torque.

[theastronaut]

I forgot to update this since I started a thread on LS1tech about it. I've found out that anything over about 7500 rpm would atleast double the cost to build it, so that's out of the picture. With a 4.8 crank and a 7500 rpm limit, the piston speed would be slowed down to the point where stock rods with ARP bolts should be adequate. I'll be boring it to LS1 bore size- 3.90" to unshroud the valves and have a better selection of off-the-shelf forged pistons.

Here's what I've come up with so far.

Aluminum block L33 5.3, LS1 bore and 4.8 crank. ~312 CI
Stock rods, ARP bolts.
Forged rods if needed.
Forged pistons.
Solid roller lifters.
Shaft mount adjustable rockers.
Double roller timing chain w/damper.
L33/799 head castings, C5 Z06 hollow valves. Send off for CNC porting?
Self built IR intake, four two barrel weber/dellorto carbs.
Hooker cast iron headers- should be fine for small CI- I want the retro look of them.
MSD LS1/LS6 ignition controller.
Drop in trap door/baffled windbags tray.
Possible fabricated/weld on wings on sump for higher oil capacity.

[Cannon007]

Yea man spend the money on the heads, I recommend these guys: http://www.mastmotorsports.com Much better than AFR and even trickflow that most guys on LS1 tech recommend, IMHO. Get the 11* heads and you can run a radical cam without running into PTV clearance issues.

[BR3W CITY]

If he's gonna go with new pistons, just get them flycut, and then mill the 799's to bump compression. No PTV issues, and would end up making just as much power. Use the money for better rods. Imo Mast heads are $1k BARE, plus you need the offset rocker arms to run them.
Spend the money on good forged pistons and rods. Flycut the pistons if you worry about ptv because of cam, mill the 799's to bump compression, use the extra cash to get them ported if your concerned about flow. You'll come out cheaper then the heads alone.

Theastronaut- I wanna see some pics of the homemade IR setup on here (I'm on ls1tech but way too lazy to go through all their threads)

[theastronaut]

Originally Posted by BR3W CITY

If he's gonna go with new pistons, just get them flycut, and then mill the 799's to bump compression. No PTV issues, and would end up making just as much power. Use the money for better rods. Imo Mast heads are $1k BARE, plus you need the offset rocker arms to run them.
Spend the money on good forged pistons and rods. Flycut the pistons if you worry about ptv because of cam, mill the 799's to bump compression, use the extra cash to get them ported if your concerned about flow. You'll come out cheaper then the heads alone.

Theastronaut- I wanna see some pics of the homemade IR setup on here (I'm on ls1tech but way too lazy to go through all their threads)

I'm sure I'll use the 799's. It'll only be 312ci, so it won't need crazy flowing heads. If a stock 5.3 will make around 400hp with just bolt ons, I probably won't need to get them ported since I'll have less displacement- porting would likely move the powerband up too high and kill any low end torque. Like I said, I'm not going for max power since it'll be a daily driver- the small displacement should get better mileage. I do want something that'll run mid 13's or quicker, and 400hp at around 3700 pound should easily get me there. I think 400 should be doable on unported heads, and with the smaller displacement it should put the powerband up higher than it would be on a 5.3, I'd be happy with a peak in the 68-7200 range. It'll be geared short (4.56 r&p) to make use of the higher-rpm powerband. It's easy enough to port them later on if I want more power.

One guy on LS1tech said that Gen 4 rods with ARP bolts would be fine if I was only going to turn it 7500 rpm? The smaller 4.8 stroke would slow the piston speed down for less stress on the rods.

Post number 5 and 8 in this thread kinda explains how I'm going to do the manifold. I got the idea from the link below.

http://m.modernhemi.com/forums/showthread.php?t=1269857

[Cannon007]

Originally Posted by BR3W CITY

If he's gonna go with new pistons, just get them flycut, and then mill the 799's to bump compression. No PTV issues, and would end up making just as much power. Use the money for better rods. Imo Mast heads are $1k BARE, plus you need the offset rocker arms to run them.
Spend the money on good forged pistons and rods. Flycut the pistons if you worry about ptv because of cam, mill the 799's to bump compression, use the extra cash to get them ported if your concerned about flow. You'll come out cheaper then the heads alone.

Theastronaut- I wanna see some pics of the homemade IR setup on here (I'm on ls1tech but way too lazy to go through all their threads)

Well if he wants to do any road racing/autox and be at high rpm consistently, like he is talking about, you will want to invest in a good valvetrain anyway. 799 heads, even ported 799 heads would get blown away by those heads and yes on a smaller CI build like his to. He is going to the trouble of creating that sweet ITB intake, it would make sense to match a big cam and badass heads for it. In the total cost of the build, its money WELL spent.

Can you setup those weber carbs for E85? Is it available in your area? if so I would think about making it run really high compression ratio's for it if its available in your area? It would help you make more torque down low, easier to tune on, run cooler, and all around just be perfect for a build like this.

[theastronaut]

Originally Posted by Cannon007

Well if he wants to do any road racing/autox and be at high rpm consistently, like he is talking about, you will want to invest in a good valvetrain anyway. 799 heads, even ported 799 heads would get blown away by those heads and yes on a smaller CI build like his to. He is going to the trouble of creating that sweet ITB intake, it would make sense to match a big cam and badass heads for it. In the total cost of the build, its money WELL spent.

Can you setup those weber carbs for E85? Is it available in your area? if so I would think about making it run really high compression ratio's for it if its available in your area? It would help you make more torque down low, easier to tune on, run cooler, and all around just be perfect for a build like this.

We have 105 octane E85 at most every station in town, and it's roughly 40-50 cents cheaper than 93. The carbs can be set up for it pretty easily, there are alot of VW guys running it. It doesn't get as much mileage, but its alot cheaper so it works out to be fairly even, plus you get the benefits you mentioned. That isn't something I've thought about but is worth considering.

[theastronaut]

After more research I've decided to go with a LS2 4" bore block. A L33 block can't be bored as much as an iron 5.3 block can, so that's not going to work. 4" bore with 4.8 crank will make 329 CI and the larger bore will unshroud the valves. I'm pretty sure I'm gunna use LS3 heads since they have lighter valves and should flow enough for a high revving 329 CI without port work. Now I've just gotta figure out how to steal the LS2 from my sisters TBSS without her knowing.
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[Cannon007]

Nice, I've actually been wanting to do this exact thing as well, (match a 6.0L block with a 4.8L stroke) So let us know how it turns out, im very interested.