I got a smoking deal on a 1977 4 speed with a ratchet top. Of course the mainshaft in the '77 is the longer length for electric starter. I'm running a set up, '60 Pan, kick only. I have heard/read, that changing out the mainshaft for the shorter shaft, (AKA before HD had electric starts on BT's), is a direct swap of mainshafts only. I can confirm its true. Took about one hour. All gaskets/seals are interchangable as well. I wanted a short shaft tranny to avoid the clutter of a starter and bearing support for an open primary belt

Hardest part was the mainshaft bearing retainer plate on the kicker side, held on by 4 flatside screws. They have a habit if freezing in place, hard to remove. Of course penetrating oil is the key here. Once you get the kicker cover off, and the tranny top off and the counter gear cluster removed, sit the tranny on the kicker side end. Look inside the case and you can see the screw holes from the opposite side of the screw heads. Spray there, let gravity work it. In about an 2 hours I then could remove them. Tap them with a screw driver in the screw heads, not real hard, do it multiple times with each.......Be patient here, if you bugger these slot heads up, you have allot of work ahead

USE a factory manual when taking apart/reassembling the tranny. The pics and setups described inside really pay off