who is running 12.1 compression and 92oct on the street successfully, and what cam spes,. and did you coat the valves and pistons? i'm planning on running 12.1 and 93oct on 225/236 .565/,565 on 111 cam {ballpark specs} with a 377cu.in. ls3

 

I don't know that I'd go that much if it's a daily driver... but my TA is around 12:1 compression, 382 stroker, 236/242 598/603 112 cam , runs fine on 93 , but I only put a couple thousnd miles a year on it

 

thanks for the reply. mine is not exactly a dd. but i sure as hell drive it a lot and it goes to the track often. can it be tamed with a bit of timing retard via the iat and ect tables? i thought a bit of extra overlap would help me get away with it.

 

12.5:1 static 8.65:1 dynamic compression on mine. No coating except the Mahle piston skirts. 93 octane premium or E85. Cam specs. in my signature.

 

I wouldn't do it with that cam, you are going to be retarding alot of timing. You will have way too much cylinder pressure. Especially in a heavier car like a GTO. You will be around 9.2:1 dynamic compression ratio, i know they are numbers but something you should look into. It will be so much safer on 11:1 or 11.5. The gain just isnt worth the risk of fighting detonation. You will have to retard it so much you will be giving up all the gains in the higher compression just to keep it alive. The intake duration and intake centerline are going to be your biggest factors in dynamic compression.