I'm just throwing this out right now, but is the front of your engine together? Meaning the water pump and fan. You need to eye ball the relation to the radiator. I bet the top of your fan is very close to the radiator face. Another way is to place a small level on your intake manifold. The small block intake are cut between 3 and 4 degrees from the factory and aftermarkets are 3.5 degree per information that I received from Edelbrock.