It is loosing the seal between the pump and the block or somewhere else allowing the oil in the lines to drain down to the oil pan level. Look very closely at the O rings and oil line fittings and maybe even the lines to fix any problems with them Are you using the stock type oil pump gasket to the block? If so get rid of that That pump only needs the O rings on the pump body and snout to seal properly
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)