Last one.....

A- "Ported" 906 head, SI brand 2.14 valve, no back cut, valve job done with a radius for bottom angle. Pinch opened to 1.070, guide boss trimmed a bit, some short turn work.
Didn't look too bad, and actually didnt work that bad in the upper mid-lift compared to a lot of what I see of these things.

B- open bowl more, relieve chamber adjacent to valve, longer top angle on valve job, a little more work on the guide boss, lay back the short turn, back cut valve...... Same cylinder as above

Lift-------A/B
.100---70.4/71.6
.200--124.4/156.6
.300--180.5/217.1
.400--229.4/255.1
.450--241.9/257.7
.500--243.8/258.9
.550--248.3/259.7
.600--248.3/258.9
.650--234.3/258.9
.700--234.3/259.7

The newer heads???
902 head(1974):
A- OE valve with back cut, grind 3 angle seat, less than 10 minute blend

B- open bowl a little more, bullet nose guide boss, pinch to 1.025", Manley valve with back cut

Lift--------A/B
.100---67.2/ 70.4
.200--139.0/142.0
.300--202.5/205.4
.400--230.5/244.5
.450--237.0/249.4
.500--240.7/254.0
.550--243.8/257.0
.600--245.7/253.2