If your head is a "270H" then the port size is the same as a stock 302 -- 1.75 inches, as i recall. Other 270 heads offer the same port size as the 228-248-256 series.
Close on 60 years ago, in his GMC Speed Manual, "California Bill" argued that the small ports were better for low- and mid-range driveability, especially on a basically stock engine.
Seems to me that changing the manifold with the "port ring adapters", were they available, would be more of a "hassle" than the "2bbl-1bbl adapter" on the 270 manifold.
God's Peace to you.
d
Inliner #1450
