I knew a kid years ago that a green over green 70-71 350 4-speed Nova with a "skyroof", would've been around 1995-1996. I remember it being a pretty solid & straight car, and he just treated it like shit and beat it's ass into the ground every time he was out driving it. Wish I could've bought it off of him, would love to have it now that I have more money and mechanical ability than back then.
I thought the Yenko Duece was a COPO Nova? Couldn't get an LT1 in the Nova. Did Yenko swap all those engines themselves? Matter of fact, I think I read about Dick Harrell getting COPO BBC Auto Novas for some stock class racing. Maybe 1968.
COPO simply stands for Central Office Purchase Order. ANYTHING could be a COPO. I have seen many, one being an Impalla of all things. If an Exec or his wife wanted something they didnt make, guess what ... a Central Office Purchase Order was issued and viola.
There were several Corvettes, one if which had red fender wells FROM THE FACTORY due to a COPO order. Terry Michaelis' 67 Corvette is one (the guy that owns Proteam). It is the ONLY 67 vette painted in Mossport green (a 66 color) and he has the documentation to prove it. I know because my insurance guy had the car before him and I helped Terry get it back from him.
I recently had a 69 Z/28 that is a "COPO" but not with a 427. It had a FACTORY INSTALLED 4.56 rear, not a dealer installed but correctly coded factory rear. Jerry MacNiesh came to the house and verified it. It was the 2nd one he' ever seen and yes, its doucmented.