f8lvenom

Hi folks, I will be building a LS3 to be boosted by a F1A on kill. Do you folks recommend keeping it stock displacement or going 416 or 427? Thanks for any recommendations.

91 Z28

iTrader: (3)

More cubes will obviously make power more easily but I think the cylinder walls would be pretty thin if bored out. If you resleeved the block then you won't have an issue or just buy a short block from Texas Speed

f8lvenom

Bringing this back up as I'm finally getting around to building this thing. Anyhow, engine builder is recommending a Molnar 3.90 stroker crank, power adder rods and DSS blower pistons. I'm somewhat leery on the stroker crank but he assures me it's fine and the extra cubes will compliment my TFS 255 heads. Thoughts? Recommendations?

f8lvenom

Mods, can you please move this to internal engine section??

BCNUL8R

iTrader: (2)

I have a boosted ls3. Forged rods and pistons are all you need. Honed with stock crank making around 1000 rwhp with an f1a-94 on ethanol with meth injection on at 4 psi. Short block was built by texas speed. I put this together about 5 years ago. The blower will make what the blower will make regardless of cubic inches. More cubic inches gives more torque at lower rpm, but peak power the blower can only do what the blower can do regardless of cubic inches. I'm actually taking timing out down low to get down the track so more torque down low isn't always beneficial when you are at 1000+ hp on the street.

f8lvenom

Builder says he’s had a few cast cranks break with prochargers. So we decided if I’m building it I’ll do it right and go with the forged crank too. He called me yesterday and said he put together an excellent combo with 3.90 stroker crank and the price is the same as a stock stroke crank. My concerns are regarding reliability and longevity but I’m no engineer or engine builder so what do I know lol.

Kfxguy

iTrader: (1)

I always wanted to build a destroked 6.2 for less torque down low but brutal top end power. Ole cleeter went to smaller engines on a couple of his cars and went faster. the coyote seems to do pretty well with only 5 liters and massive head flow. Massive head flow on a destroked 6.2 would be sick.

Che70velle

iTrader: (6)

I’m building a LS3 right now for a Grand Sport C6. I’m using a custom Molnar 3.9” crank…custom because of long snout dry sump car…Molnar doesn’t have the long snout on the shelf with a 3.9 stroke. Custom pistons also…anyhoo I’ve used Molnar in the past with great results. I did Darths 440 inch shortblock with a Molnar crank. He’s making 692 wheel without issue N/A. Molnar is good stuff.

f8lvenom

Good stuff. What pistons are you using?

BCNUL8R

iTrader: (2)

Plenty of stock bottom end LS3's with F1a-94 prochargers with no issues. The block will probably be a problem before the crank. Heck, it seems like Race proven motorsports puts an F1a-94 on a ls3 weekly if not almost daily. If there were problems with stock cranks they would know about it. Even on their higher boost 1100+ rwhp LS3 or LT builds they only do rods/pistons with a stock crank most of the time.

I'm planning to go to a 388 if/when this motor ever gives me problems. 4.125 bore and 3.625 stroke. For big boost I like shorter stroke and more "meat" in the ringlands.

I wouldn't ever blame someone for over building if you have the money, but plenty of high dollar engine builds end up having more issues than stock bottom end boosted combos or rods/pistons only combos. Plus, when you slap rods/pistons in it only if/when you do hurt the motor it's no huge loss. Heck with boost I don't even spend very much money on the heads either because heads make very little difference with boost on a typical 1000 rwhp or less combo.

In the future I want an F1x so the 388 seems to be the strongest LS combo without spending crazy money that is why I'm heading that direction.