Pump gas 440 advice

[BSB67]

Not really important. You haven’t been able to buy a 10:1 383 piston for at least 45 years from anyone. With creativity you can get there. Just curious as to how you got there: what Ross piston and what head chamber cc, and what machining.

 

[lewtot184]

A KB400 383 piston is rated at 10:1. Check out the catalog for details.