Your changes were going to net you nearly a 1.point in comp, not .5 From your ccurrent 9.9 to about 10.9 @ 75cc, more if you used the .020 shim vs the .027 cometic.
You can play with vert changes too, theres more the one way to skin a cat. From experience your 509 cam would love the jump in comp from 9.9.IMO mike
73 Sport 440, 509 cam w/Eddys 3.91 and 28.1"/27.3 tire. Et. 60 ft. 1.435, 1/8th. 6.61 @ 101.80 mph. 1/4. 10.472 / 127.78 mph. 2950# race/with me,and pump gas.
