Someone here just bought a 70 Copo Z for I believe mid forty's, and many thought that a "good" deal. A regular 70 Z is selling for what, mid twenty's? I think Phil's math is probably pretty close. Of course, there are not many changing hands right now, so as many here say, it's worth what someone is willing to spend.
I will say that I have turned down 40k for mine.
You could make the same argument about the 69 COPO's vs. Yenko's. I do not think there is a whole lot of (if any) performance differances, yet the Yenko's demand a much higher price than the Copo's. You are buying the history/name (IMHO). In fact, without the Yenko history, you could make the argument that the regular Copo was in fact superior as it was produced and sold by GM, and the Yenko's are a dealer car, therefore sort of a "day 2" concept.
Same with the 70 Copo Z's. And they are alot harder to authenticate, so when one is air tight, I would think that is worth a premium.
What HP did the 350 duece have? Not being smart, just wondering cause the last time this conversation came up someone mentioned that the 70 Copo Z's were not in the supercar class as they were small blocks and I did not think of the Deuce's then!
Of course, now that I have one I am a bit biased
Rich