Hello A Bodies, I am trying to get my old 64 Polara put back together. My question is what is the weight difference a 1967 B-body 18 spline 4-speed and a 23-spline 4-speed. Also, same difference with the 67 B-body dana-60 powerloc 4:10 and a 8-3/4" powerloc . They are complete units. Thank you...