"it was a 292, why would they be mistaken?"
Mecum would advertise whatever they are given and verification is not their thing. Also people have been known to make mistakes. So your question should read why "couldn't" they be mistsken?
As for the intake manifold(s) it appears in the pictures noted in the thread that there are 3 individual ones. I don't have any idea what they originally were but now that I've seen the photots I will ask a customer of mine who owns 2 53's. He will know for sure.
