Wow, what am I missing? he ask about factory, then his second post said 54, then you said 54? Sooooooooooo factory accessory and GM accessory, factory is factory, GM is GM and aftermarket is aftermarket. I looked up the column sold at classic truck parts and said they are different part numbers. That says they are different somehow. So that's a partial answer for No. 2. A further answer was given by TC. TC can you please look at your two answers and clarify "54 was the first year for GM Factory"... with "GM (the factory)...well before 54". Just for little ol me.
