Slant 6 225 carb?

I don't know if there is a "new" option. Depending on the year, it might have had a Holley 1920, Holley 1945, or a Carter BBS. But I don't think any of those are available new. Mike's Carburetor has rebuild supplies, but my experience with rebuilding the Holleys has been poor — they seem to have a lot of very tiny passages that are impossible to clean out once they are gummed up or corroded. I have never had my hands on a BBS. I finally bit the bullet and went with a 2bbl setup using a new Carter BBD Chinese clone, and solved all of the drivability issues.