Just in case you are not aware of this: if it is an original 1954 HydraMatic drivetrain, the engine and transmission were supposedly matched at the factory (a statement/warning about this is cast into the transmission). Also, the rear end (if it is an enclosed driveshaft) only works with the HydraMatic transmission (which is about 5 inches longer than the 3-speed/4-speed).
Also, the frame has an extra crossbar but this is at the rear of the transmission and should not be a problem.
Wish I lived closer to you (I'm near Albany, NY). I would try to work out a trade for cab/frames. I have a 5-window '54 and am looking for a '54 cab/frame from a HydraMatic.
Good luck,
Tim