I've got a stock 351W. I am just wondering if it is safe to use the stock oil pump driveshaft, or if I should get the chromoly steel unit from FRPP. I'll be buying a brand new one if I decide to use a stock op driveshaft. Does it go in through the distributor hole or up through the pan area? Also, do I need to install that c-clip thing that was on the stock unit? Thanks.