I had a careful look at the parts manual and the booster for 55-59 2nd Series and the 60-62 D.D (which I am not familiar with ) as the same Bendix unit Part #379315 Chev# 3763467
There are numerous other listings for the HD vehicles, and they are all different than the numbers listed above.
To go back to the power steering question, I checked in another Chevy truck book that I have, which states that power steering was available as an option from 55-59. The book does not include any other information. Unfortunately, that portion of the parts manual is missing. There is a picture in the parts manual depicting a 2nd series power steering unit with the pump attached to the generator, but I can't provide any more info.
Bob
