Puk'in Fluid

Edelbrock head gaskets only go on one way with water flow from block to head in back, intake only flows water from head to intake in front. No thermostat to restrict water/air flow. Run-in stand has large/good radiator w/electric fan well above intake manifold. Engine sitting slightly high in front. Pukes water out overflow or top tank w/cap removed. Water doesn't flow very fast past fill cap but appears to be flowing across the tank. Removed iron water pump and compared to later alum and found the fins are shaped opposite but this shouldn't make a difference as the rotation is the same. Need to find different radiator for car if I go top later alum pump. I doubt it is trapped air with thermostat removed. I'm tired of guessing

BCP