Best Carter carburetor upgrade for 67 383 s?

what do the primary openings in the intake measure? if smaller than 1 9/16" grind them larger or throw on an aluminum intake-dual plane. run a Carter from a 440 magnum 375 hp like I do=750 cfm, 1968-1970 ish, I picked 1 up from a swap for $100.
Primaries on intake 1 7/16" and secondaries 1 9/16".