Denny,
The 235 Hydra-Matic Rochester carburetor has an automatic choke heated by a heat tube to a manifold-mounted "stove"
The front fitting on the H-M 1/2 ton master cylinder is different. The diameter of the hole is different (I'll look for photos). There was a split block on the front. Lines were mounted differently - so brake lines were not under the transmission and rear of the engine (in case the transmission had to be removed).
The pedal shaft is different/shorter.
Greg & I know a person with an unmolested 54/55 3/4 ton GMC pickup (I forget which series). There were minor differences between 1/2 ton 54 GMC and Chevrolet Hydra-Matic equipment. But I do not know if the differences were only in the shift-linkages/indicators.
Greg will remember the color of the push button on the dash (my guess is black button on 54/55 Chevrolet).
Too bad there is not a GMC Master Parts Book on line.
Did you get the H-M solenoid starter with your transmission?
