Those Speed pros are the same ones I use, the compression listed is the dynamic compression not cranking. I have #16 heads on my car now (got them from you) and my cranking pressure is 175 LBS. I think maybe the difference is in the cam I use a Crower 60916.This cam has a later opening of the intake valve and that may be bleeding off some pressure. So you can see how two motors with almost the same parts can act different.Has to be the hole package. Do you have to run octane booster in both motors equally?
