I have a 355 with heads/pistons/rods and the compression is around 8.5. Engine is a 2bolt main with studs. Do you think it would hold 10-12psi from a 68-76mm turbo? Im going to redline at 6,200rpms with the cam I have.

 

i think you'll be fine. i know of a stock LS1 motor running 9lbs of boost through a D1 procharger with no problems at all. your compression is pretty good and 4 bolt mains are entirely necesary unless you are aiming for a 7-8 grand redline.

 

yeah the more and more I read..the more I find that the mains arent really needed unless your turning serious RPMS...at 6.2k I dont see a problem with it...anyone else?

 

Oh I forgot to mention that I have a stock very low mileage crank as well that was checked and then polished.

 

i dont think u have anything to worry about, especially if you have some dished pistons or you went up from the 53cc combustion chambers and if the overall compression is under 9, your set for sure. put premium in it and boost away.hehe

 

Its got -24cc pistons and 62cc heads the compression should be under 8.5 Im just a little worried about what people are saying that the engine wont hold.

 

why are they saying that? 12 psi shouldnt be too hard on that engine with that low of compression and especially if your keeping it under 6,500 rpm. i say its all good. no worries from me if it was my setup.

 

Ive done alot of reading and research and alot of people are saying the stock crank isnt good past 550rwhp and the 2 bolts arent either. Not to sure the HP rating at the lower RPM but I know it goes up... I think 12psi from a 70mm would be somewhere between 550 and 600 no?

 

I believe when I used an online calculator awhile ago, I got 8.5:1 with 64cc heads and -31cc pistons.

 

I've noticed alot of guys over on LS1 Tech are having good results with 9.0-9.5 Compression Ratio and 10-12 pds of intercooled or Meth/Water injection boost. The low end torque numbers would be better with higher compression ratio as long as your not detonating.

 

with a stock deck height(.020)
headgaskets .039
3.48 stroke
4.03 bore
-24cc pistons
62cc heads


the compression ratio came out to 8.39:1...whats the max boost youd recommend with the cast crank and studded 2 bolts? On 93 and on a racegas mix..

 

I wouldnt go much past 550rwhp on 2 bolt mains if it were me...

 

even with the lower rpms?

 

ever seen one on an LT1 break or any SBC under 800rwhp or so for that matter?

 

^^^^ anyone else have any advice to give?