if you are dropping in a distributor into oh say a SBC and the hole is hard to get at to see down for the oil pump drive, then mark the top of a long screw driver to coinside with the flat end. That way when you drop the screw driver into the hole to "feel" for the oil pump drive you know which way the flat is pointed. simply watch the top of the screw driver as you turn it until it reaches the desired angle and then drop in the dizzy! This way you dont have to crawl, lay, scoot yourself up onto the engine to see down the hole. [cl