What would cause the valve clearance gap to be tight, even with the screw backed all the way out?

I changed out the head gasket and also replaced my car with a rebuilt cylinder head. Also had to remove the camshaft sprocket. I set the timing and then started to check the valve clearance. I rotated the crankshaft so that the car is at TDC and that the alignment marks are aligned with the fly wheel. Then I checked the valve clearance for piston 1 and I adjusted it accordingly to the specs. That's in the book. Then I rotate the crankshaft 180 degrees so that the number 3 piston is at TDC. This is where the valve clearance is tight. I'm afraid that the valve might be down and the piston is up at this point that why it's hard for me to adjust. Is there a way I could check this or what may the problem be? I think my engine is an interference engine.