Need Help with rear axle dimensions

Dr diff told me I can convert from tapered to non tapered I just need to make sure I have the dimensions correct in order to get the correct length axles to convert it. and it was tapered on the drums, the Axle its self is standard build 241 case bolt in axles in to housing even the bearing size is the same I just need to know info on dimensions to see if it will fit properly under my 67 Barracuda.