Iron 273 4 barrel manifolds

PRH said

I don’t see the LD4B listed as a legal part for a 65,66,67,68 273 in the NHRA engine blueprint specs page.

What I do see are intake numbers:
2465726, 2535583, 2536563, 2536771

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3 of those are the factory intake casting numbers. 2465726 is the '65 273 4bbl, 2536563 is the '66-7 273 non-C.A.P. 4bbl intake, and 2536771 is the '66-7 273 4bbl with C.A.P. intake. The 2535583 you show I believe is just a poorly read or poorly cast 2536563 intake.