oil cntrol

I recently purchased a new 302ho short block from Ford. To this I added Edelbrock heads and intake,e303 cam, and a mellings high volume oil pump and pick-up. When I first started the motor the oil pressure began to fluctuate between 40 and 0 psi, and smoke began to poor from the exhaust. I tore back into the motor and found the following: upper intake plenum full of oil, burnt oil inside the exhaust pipes, lifter valley was getting clean oil but none reaching the rocker arms, stem side of intake valves looks nice and dry, combustion chamber had some oil in it, gaskets seemed fine(dry), compression is good on all cylinders. I didn't have the air pump fully conected but I don't think that would make that much differance. Obviously oil is entering the combustion chamber somehow but from where? I would appreciate any help!