Since Chevy and NAPCO parted ways in 1960, you probably have a 4X4 conversion from another company. Lots of off road rigs were, and still are special ordered for utility companies to service their power lines and pipelines.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!