1960's 727 trans verses 1980's 727 trans

Do not use a 66 or older. They require a different spline-count convertor, and the VBs are old-techc
I agree with MOPAROFFICIAL; 71s and up, are best. The TF sorta apexed in 71/72.
I don't have anything newer than 1980, and not interested in 'em either. IMO, they started a downhill spiral about that time.