Formula to shave pistons to reduce compression ??

Is there a formula? 4.030 pistons 308 heads. It’s almost 11:1 want to go to 9:1. Use: pump gas and nitrous.


If you are going to use a power adder milling the piston is a bad idea. Especially that much. You can’t make the ring land that thin. It will eat itself.

Are you 100% sure of the compression ratio? Unless you CC the heads and PIR the cylinder you are only guessing.