I remember years ago Mancini had some headers for Poly heads in their clearance section maybe they still have some left
The heads look like they could flow with some work but then you mentioned you were building a basic good running street so flow numbers at low lift should be easy to attain. Every once in a while an aluminium intake pops up on Ebay.
Did RAS make rockers for them
Gus

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64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60