I currently have a lt1 in my sonoma that has a cracked block(long story).

Ive got another block that im in the process of building a 383 with.I will be running ported and polished heads(by loyd elliot) ,cc306 with 1.6 rockers, 3.75 forges callies crank,splayed mains,6" h beams and je forged pistons.Im running a 6 speed with 4.10s in the back,truck ways aprox 3500 lbs.Its a daily driver for the most part and sees the strip on the weekends during race season.

I need an idea static compression ratio to work with here.My current ,350ci,is stock crank with 6" rods with 12:1 static cr with same p&p heads and cc306 cam.Do i need to run this much compression or will a lower cr be better for me.The engine idles as well as my freinds lt4 with a hotcam and has very little surge.I can drive around 1200-1500 rpms in 6th with very little surge.

Not sure if the is advanced enough for this section,but last time I asked this in the lt1 section,I got response from all the new guys and could not make heads or tails on what to do.

Engine builder has a je forged flat top on the shelf and says it will yeild 11.8:1 on a zero decked motor.Its this about right or do I need to drop that down some.

Thanks in advanced.....

 

-What are you running for fuel with 12.5:1 on the street?

-1200 rpm in 6th gear with that cam? That's pretty good.

 

I just run 93 octane from exxon.I have not had a problem with kr ,even with ac on in Dallas heat .

I live in an a area that the speed limit is 45 in alot of places,I drive around in 6th too keep the noise down at 45mph,That is right around 12-1500 rpms.You know it has a fairly large cam is there,but no where near as bad as one would expect.

 

From my research the static compression ratio isnt everything. You need to take into account valve timing which will affect the actual CR the motor sees while its running (ie the dynamic CR). That said I would stay at ~12.0:1 if I were you.

Here is another thread with some good info on the subject if you're intrested:

http://web.camaross.com/forums/showt...threadid=46128

 

Short answer,
The engine, providing use of the CC306, will be fine at 11.8:1. Even in the Texas heat, which I'm more than familiar with.

Take care,
Chuck Riddeck
Progressive Race Engine Development