Portcityls1

I'm planning to do a build on my ls1 but don't know if I should do a 370 or a 383 build. I've heard the 370 build is better for boost and Easier on gas mileage is this true?

batboy

iTrader: (6)

Don't know about better gas mileage, they are probably both about the same in that regard, but a forged 370 is an ideal boost motor.

HCI2000SS

iTrader: (2)

It just depends on the entire build. I just bought a 370 LQ9 forged shortblock from TMS and i'll be running my PRC 5.3 heads along with a pretty big cam and a 100 shot for now. I'm expecting around 440-460 rwhp n/a

Beau@SDPC

iTrader: (14)

You actually can't build a 370ci LS1. 370ci is obtained from a 4.030" bore and 3.622" stroke. Can't take an LS1 block out that far. You would have to start with a 6.0L block. 383ci, for reference, is 3.905" bore and 4" stroke.

That said, smaller cubic inch and shorter stroke is better for boost, thus the reason for many boosted 370ci build. If you plan to boost your 5.7L LS1, I would recommend a 3.905" bore and stock stroke, which would be a 347ci

dcam503

iTrader: (1)

I dont know much but I do know that increasing the stroke and then boosting it isn't the highest recommended way about it... I would personally look into finding 6.0l block like beau said.

garygnu

if your current ls1 block is good do a 383 forged rotating assembly .they cost $1800 and up.

monchis

I'm forging a 370 for nitrous hopefully I can pull 450+ HP.na..w some stage 2t.e.a heads

NemeSS

iTrader: (127)

i luv the ls1
but simple math tells me the 6.0 block build yields more hp capacity n/a.
i can apply the funds used for a stroker kit for the 383 ls1, for the induction on a 4.030 bore. ive been down this road before. and this my opinion based on personal experience. not bench racing

jonesjgqg

they are probably both about the same in that regard