shifters

can i make my three speed shifter a four speed shifter or are they entirely different parts?

How do you mean? I think the threads on the shifter knob are the same for 3 spd and 4 spd... And you could always cut and weld or make a bracket that uses the 2 holes from the 3 spd and bolt a brace that would connect the two shifters beneath the shifter boot. I believe that they bolt up to the transmission differently, though. You could figure it out if you wanted to use it, I'm sure. =)

3 spd has 2 levers for 2 rods. 4spd has 3 levers for 3 rods.

The mount of the tailshaft has different pattern. The levers that attach to the studs that come out of the box result in a different position, and I have a doubt that the knob will interchange. I know the rubber boot is the same for each.

Wm.