Why won't this manifold fit!!?

[Bluegrain64]

I need to replace my cracked exhaust manifold on my 64' 292 c30.

I've posted before on this subject so try not to flame me! I had some excellent answers regarding OE used manifolds but I'd like to go new if possible.

I have no clue why this says it will NOT fit!

It says it will fit 65-79 but not 64...

Were 63-64 292's different? Previous answers from my other thread say no, all were similar until the intergrated ones came out.

Thanks for any help/insight.
https://www.amazon.com/ATP-Automotiv.../dp/B000IYCY3E