ok stock LS1 with stock ls1 heads is 10.5:1 compression.

when i switch to 243 heads what do i get?

and how much of the 243 heads do i have to mill to get 11.1:1 ( or real close) and if i mill that much will i have valve to piston problems?

thanks
D

 

bump, found this during my search and I'd like to know too

 

the stock ls1 with ls1 heads is 10.1:1 with 243s it will bump up to 10.5:1. This thread has a lot of good info in it.

https://ls1tech.com/forums/advanced-...ume-vs-cr.html

 

and 5.3s would be 11;1 ?