You can take the rear housing & speedo parts from the 4 speed & put them on the 5 speed. I would use the 5 speed. It,s the best of 2 worlds. You can use 4th when you are pulling a load & 5th when you come back empty. Those 292,s are tough. I used to maintain fleets of 1 tons & we had mostly 292,s. I,ve driven them for miles wide open, never letting off the gas. The only thing they are hard on is exhaust manifolds. Ive got a T-5 behind a warmed 350 in my half ton, although i don,t haul anything I get on it once in a while & have never hurt it.
