I have a '74 3500 Step side long box dump truck. I've been told at various times that you could order them with that option, that some dealers installed it with or without Chev's blessing, and that it was only available as an after-market addition.

Whoever installed it did a professional job...hoses are neat, everything works well. The hydraulics run off the transmission Power Take Off.

Just out of curiosity, does anybody know whether the dump option was available from the factory or whether it was aftermarket?