Well, if it were mine (I wished), I would try and find a quality take-off. But there are repros put there.
They (repro) seemed to be copied off the 57 292-312 engine but according to cataloging both styles/years take the same inlet pipe.
I read one comment on the the repro where the buyer had to have surfaced the manifold to head surface but you are most likely going to have to do that with a take-off.
For model specific, the CASTING ID NO is ECH-9430-A (both FORD and BIRD)
They are available as take-offs on EvilBay -
____________________________