The valves should both have .002" - .004" clearance.
The mid point of the valve overlap event should be around 5 degrees before top dead center. Be sure you are turning the prop in the direction that the engine runs.
The timing mark on the cam should be in alignment with the the lifters at top dead center. The mark can point exactly at the lifters or opposite.
The cam turns half the speed lof the crankshaft.