I got to reading in the internal engine section and some guy had a thing going about compression and cam size. It was mentioned a healthy cam in an LS1 (like Trex stature) could support 12.0:1 on pump gas! Anybody know what an LT1 can do as far as CR goes with bigger cams? Just out of curiousity............ Oh btw, what's the stock combustion chamber size on the LT1? I don't even know.

 

Dont fully understand your question but, the stock Combustion chamber is 58cc

 

Well I never thought about it much but he was making sense. The bigger the cam, the higher the compression you can run due to the overlap reducing the dynamic CR. I was wondering how much CR an LT1 could support on pump gas.

 

I'm running 12:1 on pump gas. big solid roller though.

 

I have a 355 with a CC306 cam, 51cc heads, 0 deck block, -5cc pistons and .039 head gaskets. Which brings my compression to 12.335:1. I run that setup on 93 octane every day. No problems at all.

 

Wow! That's up there. Reverse coolant flow must help with that. I should've hit higher on mine as well. I'm going with a bigger cam but my CR will still be low. What kinda power does that sucker make? Better yet, what are your times? I'm curious as to how much power lies within a couple points of compression.

 

I'm not sure how much power it's making as of yet. I have not had the chance to finish tuning it and get it to a dyno. I will say that even with the bas tune, this thing PULLLLLS above 3000 rpm. Once I finish tuning it and get a 12 bolt, it'll be track time

Scott

 

i'm close to 13 to 1 on pump gas. this is pushing the limits even with my cam
264/270 @ .050" .680" . the motor only sees race fuel at the track but it does run ok on pump gas in street trim.

 

holy christ that's an enormous cam, what size motor are you running? How bout times?