Well, my 61 Parts book says.....the Heavy Duty tans for a slant 6 that the Pinion (MDG) is either 24 splines or 18 splines and is 13" long. and for the big cars (Desoto, Chrysler) it is 24 splines or 20 splines and 13" longThe smaller cars had several different spline and length combos that won't work for you.