[YENKO DEUCE REGISTRY]

Welcome to the site Allison.

I would speculate that the car your father owned was most likely one of the first 50, and probably one of the ones that was sent back to GM by Fred Gibb Chev. The additional 19 ZL1's appear to have been specifically ordered by their selling dealers, as opposed to 'fleet' ordered like the Gibb cars.

Using this speculation would narrow down the possibles from 12 to 10 by eliminating car #'s 60 & 65.

It would help if you could tell us if your father's car was an automatic vs. a 4 speed, this way we could narrow it down to 1 of 4 a/t's vs. 1 of 6 4 speeds.