John,
I agree that there is value to them. For someone that is trying to do a '67 restoration or for that matter, installing a 400, 430 or 455 into a '65/'66 A body.
If I recall correctly, those are the same as the ones I used to install a 455 in a Skylark some 20+ years ago. If I recall, at the time , the headers were the hardest part to obtain.
Loren