I would make sure that the pick-up tube doesn't have a crack in it and that it is sealing good inside the pump. I weld the pick-up into the pump, but have seen the tube have a crack before. Also, no gasket between the pump and the main cap, but do make sure that the cap has a good sealing surface and doesn't have divots or cracks causing leaks. I use an ARP oil pump stud and nut, but make sure that it doesn't thread down too far into the main bearing.
You might also want to make sure that the oil is draining back down into the pan OK. Because that is a way to go through the 7 quarts, if it is staying at the top and not draining quickly out of the heads and past the lifter screens.
I don't think that you ever mentioned what weight of oil that you are running.
Bill M