Date code: Hurst Comp/Plus?

[jeffschevelle]

I don't know about the factory installed units. But on the undated OTC Hursts, that patent number in the first pic above was issued 11-09-1965. I don't know how long after that it took them to retool to add the patent number stamp, but I do know they were still selling them with "Patent Pending" on them until at least Dec. of 1966.

My 67 Chevelle real day-2 drag car had a "Patent Pending" unit installed in late Dec. 66 or very early Jan. 67, just days after the car was bought. Of course, it could have been in the speed shop's inventory for a few months before the original owner bought it.