Generation IV Internal Engine - Needing advise for an LS3 build




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01turboformula
06-17-2012, 11:01 AM
I just recently purchased a bare LS3 block bored .020 over. I plan on sending it off and getting sleeved to make a 427 out of it, but I'm not too sure which direction to go as far as which h/c combo to use, and that would also work with boost. I would like to make a 10 sec street car out of this build, I also want to know if my 4L60 will work with the motor if I was to get it built up as well. I'm still a newbie when it comes to builds so any advise I can get will be greatly appreciated. Forgot to add that this build is for my 01 f-body.


COPO9560
06-17-2012, 11:35 AM
If you are considering boost, you don't need a 427. There are folks running 8's with stock cubes and a lot of boost. Best path for a very fast and expensive car.


A sleeved 427 can get you into low 10's (or better) assuming the right drive train and suspension are used. As for heads, the LS7 based are a great fit for 4.125 bore and there are a number of great suppliers for these. MAST, AI and WCCH all have offerings that will allow you to build a beast.

4L60, properly built, can likely survive behind the 427 so long as no boost is added.

All that being said, easiest and least expensive path to 10's would be to build your block into a 4 inch stroke 418, ported L92 or aftermarket heads and add a small shot of N2O. The 427 build will be significantly more money than the 418.

Good luck,

01turboformula
06-17-2012, 11:47 AM
Soo a 427 would be a good build as long as i stay away from boost and a 418 would be good for boosted applications? Which build would you recommend i go with?


A.R. Shale Targa
06-17-2012, 12:34 PM
Soo a 427 would be a good build as long as i stay away from boost and a 418 would be good for boosted applications? Which build would you recommend i go with?
Both 418 and 427 engines can get you tens with no boost. As stated the 418
would be a little cheaper to build because of the 4" stroke vs. 4.1" of the 427
which requires block grinding to clearance for the rods.
I'd put a stock 3.62 crank w/nice Compstar rods and Diamond pistons and
some 317 heads and have a low compression boost friendly 380 CID engine.
You only need a T4; 74-76mm turbo and a pump gas like 8 lbs. of boost to
hit the mid tens. Do TONS of research....best of luck

01turboformula
06-17-2012, 12:47 PM
With the 380 what size rods and pistons would i need if the block has a 4.080 bore? Are the factory ls3 heads 317s?

A.R. Shale Targa
06-17-2012, 01:35 PM
With the 380 what size rods and pistons would i need if the block has a 4.080 bore? Are the factory ls3 heads 317s?
Many aftermarket pistons use a GEN I .927" pin bore and work with 6.125"
long rods which are .027" longer than stock length.
I assumed you were going cathedral runner heads/intake, 317s are common
6.0 liter truck and SUV which are readily available and have large combustion
chambers to help lower the compression ratio for boost. LS3 heads would
also work but you need the corresponding intake and offset intake rockers.

01turboformula
06-17-2012, 01:52 PM
What intakes would work best with the 6.0 heads? Would it be best to get a custom grind cam?

A.R. Shale Targa
06-17-2012, 09:51 PM
What intakes would work best with the 6.0 heads? Would it be best to get a custom grind cam?
the FAST intakes are the best but you can make great power w/LS6 or the
truck intake if hood clearance is available. I used EPS for my cam but there
are several vendors that can spec one for you. Even a Thunder Racing 224
would fit the bill nicely with a wider 114 or 116 lobe separation.

CAMSTER
06-17-2012, 10:26 PM
The simpler the better, a 416" ls3 will get you in the meet tens with ease, and is simple to keep under hood temps in check, a problem with too many hot pipes inside the hood, on a boosted DD.

For rods, don't skimp here, go a couple of hundred horse power rating above your intended top HP, so you'll need to find out the HP rated rods you need, this you have to make sure off.

For cam, got to nail this one as well, Camhelp@guerragroup.com .

But if you insist on boost, then be sure to get heads made to use with boost, like LS9 or LSA, or any head with really thick decks, unless you love to change head gaskets, and can afford to keep the car down and stay working on it.
And this rout you don't want to stroke it, keep stock crank unless you plan to really turn up the power later.

01turboformula
06-18-2012, 06:14 AM
Thanks for the info, I'll definitely take all routes of the build into consideration. I'll post up which build I've decided to go with to see if I've made the right choices for the build. Again thanks for the help.