I saw your other post regarding that 68 BB (big block) Camaro where the trim tag and vin didn't go together, and now I see you are looking at this 67 BB camaro. So my question would be:Do you want an original big block camaro that is all numbers matching, and you are willing to pay the big money because of it?
It sounds more like you want a Camaro with a BB to drive and cruise in, and not have to worry that the car was illegally hacked together, or that it will be a 1000 gold car at some show.
IMO on this car, since there isn't any documentation, you have to somewhat treat the car like the guy just added the 427. If the body is clean and the trim tag, vin, and secret vin all look good, and the title is good then it is worth making a reasonable offer.
How about a pic for us? AND how much is he asking?