The 1954-55 1st trucks have a different steering column mounted shifter housing than the previous years. These parts are very rare and $$. It is typical of Chevrolet to not re-invent the wheel so some of the shifter parts for Hydramatic trucks were originated on cars equipped with PowerGlide. Try looking for shifter reproduction parts for 1953-54 cars (also earlier years) equipped with PowerGlide Transmissons. Modification still required. The last attachment is a truck housing with dial and bezel. The trucks with Hydramatic also had an assembly mounted on the steering column before the firewall that provides shift position detents and also has the neutral safety switch that prevents starting the engine when the transmission is in gear.
Having said all the above and the complication involved, you probably will be better satisfied making your own shift indicator.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
