O-M-R
1972 Buick GS 'Stage 1' Cylinder Heads
Casting #1238148
Same casting as the GS 455/250 HP Cylinder Head with 2.00" Intake and 1.65" Exhaust Valves.
To convert to 'Stage I'
The 'Factory Techs' performed the following;
1} Opened up the Valve Throats
2} 'Ported' the Valve Bowls.
3} Valve Guide Tear-Dropped
4} Choke Point Widened
5} Push Rod Pinch 'smoothed'
6} Valves Unshrouded
7} Intake Valve = 2.130"
8} Exhaust Valve = 1.755"
9} Valves Back-Cut