Match Race 1972 ~ 'Duster 340 vs 'GTO 400'
1972 Pontiac 400/250 HP
Cylinder Head..... 7K3
This 'D-Port' Cylinder Head was actually pretty decent for Mild to Mid-Range Performance and Street Use.
They had a pretty good flow-rate through the ports.
Intake = 206 CFM @ .500" Lift
Exhaust = 161 CFM @ .500" Lift
On the 1972 400/240 HP Engine, they came with 'Screw-In Studs' and 'High Load-Rate' Dual Valve Springs.
You could also mill the Hell out of them, and take as much as .070" off the Head surface.
.0048" = 1 CC
1 CC = +.12 Compression Gain