i have a 1972 400 big block rebuilt and doing last minute replacements on these few parts and can't seem to get it correct...i am trying to install both temperature and oil sending unit...the problem is that o'reilly's auto has both parts as oil sending unit as S330 part number but its treads are to big so is the canister itself, the temperature sending unit is part number wt127 it also is small and what appears to be incorrect..i have a temperature switch located by water neck where the heater hose nipples are located and the temp switch in the block is alot bigger treads and overall bigger in diameter..PLEASE HELP IF YOU CAN WITH THIS