[Lynn]

By unbiased, I am assuming you mean someone with no dog in the hunt.

Obviously, the engine for either the Yenko, or the non Yenko COPO is much more to the owner of the vehicle that "belongs" with the engine. Anyone else is just wanting to brag that he or she has a real COPO or real Yenko engine in his or her project.

For anyone other than the owner (and because the current owner doesn't care to re-unite, I am guessing you are talking about value on the open market to anyone else), I don't know that the fact that the engine was originally in a Yenko COPO is any greater than a non-Yenko.

Having said that, because of the Yenko mystique, the same engine out of a Yenko would carry a premium. How much? Guessing it would be comparable to the premium of a Yenko car that was all "born with" power train vs a regular COPO car with all "born with" power train.

That is a personal preference for a potential buyer. But I am sure you can track the difference in cars sold over the last few years. I have not tracked, so can't tell you.
Then just extrapolate. For instance, if there is a 20% difference in complete cars, maybe there is a 20% difference in complete engines.

For me, personally, I wouldn't pay a premium at all. But, I recognize the mystique, so there are probably some out there who would.

Probably the smartest avenue for the current owner of the engine is to wait until the car sells at auction, then market it with the VIN posted and hope the new owner wants to reunite.

JMHO, and worth about what you paid for it.