I did the same as moper . Just took an old rod form a dead motor and welded some scrap 5/16 steel rod to the end and ground some flat spots on the end for it to fin in my drill. Works great and I even painted it too.
Just remember if its a small block it is turned clockwise and bigblocks are counter clockwise. I have the moroso tool and I welded a 3/8 drive socket on the end and I turn it with my electric torque wrench. I can get it up to 30-40psi. The best way is to have a friend turn the crank with a breaker bar while you are spinning the oil pump. That gets oil everywhere.