#920 vs. #675 Heads "Compression vs. Cylinder Flow"

66fs said
Cast Iron Pistons? What top angle did you narrow seats with, or is that classified? Thanks for all the 273 info by the way.

I meant, Factory Cast Pistons

Sorry About That.... 'Cast Iron'..... :banghead:

Valve Seat Angles.
Intake...... 60* ~ 45* ~ 37* {Top Dress 20*}
Exhaust.... 60* ~ 45* ~ 30* {Top Dress 15*}