Carter/Ball carburetor- Help ID

That Carter BBS you're showing us is a bit of a mongrel. It has the main casting from a '71 (+'70 California) carb, but the top casting/air horn from a '70 (49-state) carb. It will work, but you won't be able to hook up the evaporative emission control hose that runs from the body of the fuel pump (not its inlet/outlet fittings, but the body near where it bolts to the engine) to that top-front hose nipple on the Carter carb, the one that's capped off. No big dealbreaker; you'll just have a stronger raw-gas smell around the car when you shut it off with a hot engine, especially in hot weather.

Of the two carbs, the Carter is the better design, but carb condition is more important; a brand-new Holley 1920 would be preferable to a beat-to-hell Carter BBS. Go through the Carter with a good quality carb kit from Daytona; ask for a kit for a Carter BBS 4716s and you'll get the right kit. Even the best kits no longer come with a usable float gauge, you just get a useless strip-of-paper ruler, so see here. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.

The Carter's fuel inlet is on the front rather than on the side like the Holley, so take that as an excuse to do the Fuel line mod.

(for many years I thought "Ball & Ball" referred to the two check balls inside the carb, but that's not so; it refers to the Ball family who had a carburetor company that was later bought out by Carter with the assistance of Chrysler chief engineer Carl Breer; see here)