1965 Valiant slant-6 225 carburator

Stock would have been a 1-barrel carb, either a Carter BBS or a Holley 1920 (depending on what came to hand when that particular engine was being assembled at that plant on that day at that hour and minute).

The Motorcraft 2100 is a very good carburetor, and if it's done right this swap onto a Slant-6 can work very well. "Done right" means the carburetor is selected properly for size (1.08" venturi is the best pick) and it's mounted on an intake manifold correctly configured to accept it—either a modified stock manifold or a 4bbl intake with a 2bbl adaptor plate—not a cheezymatic 2bbl-to-1bbl "adaptor".