I'll chime in here......
This is all good stuff and spot on!
I grew up with both Mustangs and Corvettes in the family and my Dad still has both.
In the Corvette world, all engines were VIN stamped on the pad over the machined broach marks adjacent to the mating head surface. All date codes were always before the build date of the car - nothing new here.
However, it has become perfectly acceptable in the ultra-anal Corvette community to assemble/build a date code correct engine, resurface the block, apply new machining broach marks (though not always) and re-stamp the block accordingly. For the most part, owners disclose that it is numbers matching and date code correct but not the engine that it was born with. Gives a value of approx. 90% of a true orig. engine car as opposed to 70-80% with just a replacement engine. There's always a few ethically challenged owners out there that won't disclose.....searching for that almighty $$$.
That being said, if you're an un-informed or mis-informed buyer purchasing a #'s matching car, be it a Ford, Chevy, Mopar, etc., the burden lies with you, the purchaser, to perform the proper verifications.
This particular case, the owner purchased just that, a date code correct, numbers matching '66 K fastback. Unless you've studied numerous original VIN block stamps, whose to know the difference. Walks like a duck, quacks like a duck.......it's also listed in the HPMX registry accordingly.
Now, out of the blue, a fellow HPMX member and K-owner winds up with your 'real' original engine with a verified VIN that matches your Kar....uh-oh, now what?? Your Kar is now worth approx. 10-15% less today than yesterday - bummer. Course of action would be to try and make a deal to purchase the engine and move forward. It's value lies in what it's worth to you (fair or not)to put your Kar back into the Orig. Engine / #'s Matching category. If the price exceeds the percieved added value, then pass. However pass with caution as it's extremely rare to be given the opportunity to re-unite an engine with it's original Kar - at any price!!
For pure logistics (Like in the SAAC Registry), a notation needs to be made in the file on the said Kar with new information about the engine re-stamp. Also, that the original engine has surfaced but yet to be re-united with said Kar. Information to follow.....
I hope this gets resolved with an ammicable and happy ending!!
Mark
<i></i>