'72 Buick 455 Oil psi Drop
I freshly rebuilt the 455 and had made various oil modifications for higher rpm usage. The two main modifications were a high volume/psi oil gear set and a lifter valley crossover tube in the rear of the engine. I have the pressure sensor installed at the rear of the engine at the lifter galley. Initially, at a cold start I have 75 psi. After 30 min or so at 200 degrees, the pressure drops to 25 with 30w oil at 500rpm. AT 1000 it is at 50 and increases to 75 with a little higher rpm. Is this anything to be concerned about? I know the oil gear housing may be a little worn and scored and the pressure is being taking from the back of the engine, but it seems like quite a pressure drop for a freshly overhauled engine.