Does any of you knowledgeable users have a table which will give an estimated psi for any set CR?
Like 10.0:1 = 200psi ....

Knowing that there are a lot of variables that impact these number.

And with AL heads how high can the compression be before you start having detonation problem with Pump Gas, 89-91 octane.

 

Basic, barometric pressure =14.7 PSI at sea level....147 lbs would be 10:1...Pretty close if you divide your number by 14.7. There are several things that can affect your numbers, but that should get you in the ballpark....aMP

 

I totally forgot about that. There is a lot of conflicting posts having 10.0:1CR from 160-200psi. It least 1 was close.

The bigger challenging is getting all of the parts together for a specific CR.

 

Actually figuring all the areas (CCs) of the parts and doing the math will get you very close. Cam overlap can play a role, but you have to get pretty radical to change it much. Another note, when doing a test with a gauge screwed into the plug holes, all the plugs need to be out, and the throtle plates in the carb wide open....aMP