this may help you decide Cylinder Heads Flow Data at 28" H2O
Manufacturer /Part Number Port/Vol
Intake / Exhaust Valve Size Intake / Exhaust Combust. Chamber Volume .100"
Intake / Exhaust .200"
Intake / Exhaust .300"
Intake / Exhaust .400"
Intake / Exhaust .500"
Intake / Exhaust .600"
Intake /...