Tom, I've run 0.050" total on a big block intake, at 0.00" deck with a 0.042" Cometic head gasket. I've run tighter than 0.070" on the exhaust, but I know that I have kissed the piston with a valve or two when the exhaust valve bounced on the seat. I know valve bounce can happen, so I won't tell anyone to run tighter than 0.070" on the exhaust. Valve bounce on the intake will not cause a clearance problem, just beats on the valve job and makes Jimmy Bridges chew me out.
