I have a 1969 short wheelbase F250, 390 I'm trying to fit a spool to the dana 60 but it has 16 spline axles and spools aren't available. I have read that I can use 30 spline axles for which there is a spool. I'm looking to purchase used 30 spline full floating 33.5" long axles . both sides are same length

thanks...Joe