Im planning to buy an LM7 based 347 short block and put Trickflow/Tooley fast as cast heads on it with 64cc chambers. I will use arp studs and gm mls gaskets. I have the choice of shelf pistons in -3.2cc or -11 cc. I’m thinking the -3.2cc and depending on deck clearance would put me around 10.7 to 1 static. Fuel is e85 and cam will be either the jam cam or a custom cammotion grind. Boost level will be around 15 psi to start, but I want around 800 rwhp eventually so what ever boost it takes to get there.

Lets avoid telling me how you make more with $300 junk yard builds all day long and stick to the topic of compression ratio on this build. Boost will be from my current D1x procharger.

Sorry it was early...with the choice of -3.2cc or -11cc pistons and the other information about the combo which would you choose? Off the top of my head I think the difference was either 10.7ish to 1 or 9.8ish to one depending on the unknown deck clearance.

Ok that makes me feel better about the 10.7 to 1. My car is primarily a street toy with trips to the track. So with the small cubic inch centrifugal setup in a heavy street car the higher compression should help I was just afraid it would be too much.

As always appreciate your input.

We have a 377” running 26+ psi on pump E85. Its at 11:1 CR.

Good tuning and run it Hard!

Best of success with your build.

I’m 10:1 with Jam Cam. Love my street toy. Many centri set ups here with 10.7 that have had great results. Jam Cam @ 6* overlap & E85, I would think you have a great set up. It’s all in the the tune.
Take a look at Detoxx, I’m pretty sure he runs a ProCharger with substantial boost @10.7.

Yep 21psi, SBE LS3, 10.7:1 CR

How much timing are you able to run?

Mine is at 15 or 16. If I had forged internals I’d bump it closer to the 20’s if it likes it. Im
gonna bump the CR into the 11’s also when I do it.