Re-installed heads w/only all the exhaust valves w/checking springs installed. No pushrods, and mechanically opened each valve to the maximimum valve lift that this camshaft has. This allowed me to turn the crankshaft get the throws out of the way for realworld accurate measurements between the cylinder wall and the exhaust valve. Sounds corny but used a measured paper clip as a wire gauge (.029") and each valve had very close to the same clearance allowing the paper clip to slide easily through between the wall and the valve. Increase the valve lift and the clearance goes away quickly.Not high tech but pretty darn accurate.I used .690" as my lift number. Ithink a.750- .800 lift cam (actual) would have trouble here in this 4.350" bore. I talked with the tech dept at Hughes engines,(where the heads were purchased and ported) and they said the've had no complaints at that bore.
Just doesn't look like any camshaft upgrades at this bore. Thanks for all the input here. Bill