I am running a 416 with 12:1 with xheads on pump gas. No problem. Xheads are open chamber which are about 13cc this lowers the compression to 10.73 good to go with 93 oct works fine race gas on race day. : )
I don't get this post. Which is it? Do you have a MEASURED 12:1 or are you guessing and going off published data (which is never correct) or are you a MEASURED 10.73 or are you guessing and using published numbers?
Just want to clarify because it confused me, keeping in mind I am very easily confused.
