Holley 1920 replacement
Auto or standard? The super six setup will need the kickdown linkage with it if you have an auto...or an aftermaket cable like a lokar. There is a 2 barrel motorcraft that works. Dan will know.
Will need an aftermarket electric choke too as the chokes are different between 1 and 2 barrels.
What wrong with your 1920. A good rebuild kit and cleaning the metering block might do wonders...they also came with 1 barrel carters.
Easy to over carb a stock slant with a 4 barrel id bet