Super Six Conversion
You will need a different kickdown linkage. Original Super Six items have grown scarce, but user "Michael" over at slantsix.org might have one for you. Otherwise see
this thread for kickdown options.
You'll need a Super Six air cleaner if your car has A/C. If no A/C, you can make a V8 air cleaner work.
You'll need a shorter throttle cable; that's a Pioneer CA-8417 or ATP Y156 (same cable for V8/A-body applications)
You'll need a different choke thermostat, a № 1232
electric choke kit is the way to go.
valve adjustment is important on Slant-6 engines, but does not differ for 1bbl vs 2bbl carburetion.
It is very much worth your while to get the
good gaskets for the manifolds-to-head and intake-to-exhaust junctions.
Cheap carbs = endless headaches trying to make the car run well, so shop carefully.