Shouldn't need to shoten the driveshaft, I didn't. It doesn't necessarily need to come out of a truck, either. A passenger car version will work just as well (mine came out of a station wagon). You can substitute the original relay for a 30 amp rated headlamp relay, I used one with a built in fuse from Standard-Hygrade. The kickdown isn't 100% necessary, and are very hard and expensive to get (you don't want to know what I paid for mine, and never have needed to use yet). While this isn't an issue with yours, those doing this with the '55s will need to swap the side cover to the pickup 3 speed side cover, as they are different.
BTW, if you can get me the codes off the 3rd member, I can decode them for you to get the gear option. The numbers will be a 2 letter and 2-3 number code stamped on the passenger side of the center section,
in this location. Close up of what the code looks like.
