J lee,
Okay, so you put the right gasket on the oil pump, but did you put it in the right position? It is easier to get this wrong than you might think. I have managed it myself, though once I did, I learned the hard way and haven't done it again.
Are you certain that the oil pressure relief valve was installed? correctly? How about the camshaft retainer plate? If it's left loose, you won't have a lot of pressure, if any. Other than that, most everything that contains pressure is a wear surface.
Did you crank the engine, ignition disabled, plugs out, to try to establish pressure before starting?
Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon