[DD931]

My '48 F-1 had a four-speed from the factory. I converted it to three-speed about ten years ago. Drives like a new truck! Lots of differences between the two assemblies. Different mount, different driveshaft, different u-joints, different yoke. Whatever path you chose, the first thing you have to do is replace that butchered cross member. Form my point of view, I would strongly advise against using the four-speed. They are terrible from a drivability perspective!!!