Originally Posted by hcompton
You always want to shoot for lift in the 25%-35% of valve size. So .5 is just about right for a 2 inch valve. Yours are almost .2 bigger so .6 is perfect. .7 would still not be out of range. Less and the valve is a restriction in the intake track.
With small chevy the valve size of .6 is all you ever need with 2.02 valves for the most part. But big chevy can have a much larger valve and will need the lift to work correctly. lower lift will still run but it will not get effecient like it should at the cams VE rpm range. If that makes since. Sorry i know i left about three books worth of info out of that one. LOL
You're assuming the port isn't a restriction, and it also depends a lot on your throat size and valve seat.
NONETHELESS, L/D=.25 is in general a good target to hit with a good head on a hot street engine.