After some research, I've noticed that if full flanged Ford small block headers are finely centered against a 318 poly head, the two inside runners will be too wide by .040" each, forcing the two outside runners to be off by .080". So if a section .080" wide is cut from the center of the flange, and then the flange pushed back together and welded, the two inside runners will be a match leaving the two outside runners just .040" off each, which could be fixed with mild runner matching.

Then, if the flange is wide enough, or extra material is welded on, the flange could be drilled for the mopar bolt pattern (which is different).

If one already has the ford headers, and clearance (starter, steering, etc.) is not a problem, it seems like a cheap way to get headers for the 318 poly. Anyone disagree, or has anyone tried this? Thanks!