Stop in for a cup of coffee

here's a 'competition' series. Looks like it has both bolt patterns. supposedly a 625 cfm - which is plenty for your 318. Could check the number on it.
Carter AFB 4 barrel carburetor - Competition Series 625 CFM | eBay

or you could pick up a mopar one., I'd look for something pre-68 so you don't have to deal with CAP/CAS calibrations and restricted adjustments.