H-M and Manual trans. torque tube measurements.
Torque tube length and how to measure.

Torque tube length
1948-54 Manual trans. 60 1/8" , 3 and 4 speed tranny's
1954---- H-M trans.....53 7/8"

Propeller shafts are different lengths. Type C
1948-54 Manual trans. 63 7/8"
1954---- H-M trans. 57 5/8"
Splines are the same on both. 17
SOURCE

I think that is the only difference between the H-M and Manual trans. torque tubes

1954 Chevrolet 3105 Deluxe Panel Truck
w/Factory HYDRA-MATIC