how much compresion is to much for pump gas?

 

Anything over 10:1

 

Not with computer controled cars anymore.

 

Alot of things can affect what fuel you can run, aluminum vrs. cast iron heads head design and something called dynamic compression which is controlled by cam choice this is a calculator that gives you an idea of fuel octane requirement http://www.hotroddersauctions.com/Dy...Calculator.php