Add your abody driveshaft length for quick reference

ok so not to threadjack but can anyone tell me how long my driveshaft should be for a 318/904 to a 7 1/4 rear for a 73 duster? does anyone know if the splines of a 73 3 speed manual are the same as a 904 in other words would a driveshaft out of a 225/6 3 speed manual 7 1/4 duster physically work with a 318/904 7 1/4 rear end ? thanks, im sure there is a thread on this but i cant seem to find one...