I've seen this debate rage on for a while now. Years back (80s) I saw a lot of rebodys done on rare cars. The point was, Before these cars were bringing heavy money, the emphasis was on having the best restoration possible. Most wanted a pristine body over having the original that was hacked/patched/rusted, or fixed (and I had the same people tell me my pristine 70 nova SS 396/375 HP original motor/trans/rear/paint/glass car with 39K on it was only worth the sum of it's part because I had no paper work to prove it, other than talking to past owners). And that took precedent (for them) over having as much of the original car as they could. I'm not advocating this stance, but this happened ALOT more than you think. I can think of 1 L-79 Nova, 1 COPO Camaro, 2 COPO Chevelles, at least two ZL-1 camaros (That just the tags were bought) and 1 Z-16 just off the top of my head that were body replacements. And this was just as they were finding the hidden VINs on the 68 and up's so I imagine the COPO stuff somebody took a hit on.
I have a friend that had a sister 375 Nova to mine. He rolled it over in the late 70s and the body was destroyed. He still has the undecked original block, rear end, numbers,most of the parts, all the paperwork, ect. Should he toss the paperwork, and sell the block so somebody else can deck, rebroach, and restamp it, ect? And another who was the original owner of a 67 Chevelle 396/375HP car. He found it in the 80s, bought it back (it had no rust, but was cut up for racing) I think he spent 25K in 1980 money just putting the entire floor from rocker to rocker, Top of firewall to tail lights in from a rustfree donor car and having it straightened and painted (you'd never know, it looks that good) then collected the rest of the parts (the car was stripped). How much of either of these cars carry their original parts? where do you draw the line? And I'm not talking about selling them as anything different than what they are. I know if your buying, and paying top dollar you want to know exactly what your getting, but do you not call it a real SS because the numbers say so, but you replaced the body, or is it really not a 375 HP because there isn't one thing from the original car on the motor, but the papers says so? Interesting argument, Huh??
That being said I still have the numbers and titles from and 350/396 Nova SS, a 69 396 Chevelle SS, 66 Nova SS, and others including a 55 (the VINs fell of a lot). These were cars that were a considered to be junk in the 80s (condition-wise). Why'd I save them? Like most others I threw them in an old cigar box in my garage because it was something to look at down the road. I've had offers to sell a few of them, but never did because I didn't want the hassle down the road of somebody trying to pass them off as something they wern't. But with the prices of these cars now I can imagine somebody having the parts looking for numbers. Hell, I never thought I see the so-called "Clone" market take off like it has. With the price of parts nowadays,, I was thinking of buying a 66 SS Nova clone to cut up figuring it'd be an easy way to get trim and parts to sell off......