Should I leave it Stock?

The engine does not suck on the carburator.
The pistons go down and create a low pressure area, which the atmosphere then tries to fill.
Your tight-gap plasma-Moly rings and perfectly round/not tapered/ not ridged, 50plus year old cylinders (cough-cough,lol) are gonna set the stage for how low a pressure your engine can create. This sets the stage for how much air is gonna find it's way in there. Next are the restrictions of the intake valves , the runners and the throttle bores. And finally, the cam decides how long this column of air is gonna be allowed to flow. If your engine can physically only induct 300cfm of air, then it matters not in the least as to power, how big a carb you put on it.
Your 2bbl is good to ~3600, It will flow enough air, to about 3600, to not hold your 273 back.So 3600 in first gear with 2.76s is 33mph and say you are gonna shift at 4400 so that will be ~44 mph. At the shift the Rs will drop to 2600, and then,second will hit 60@3300. Wait what? That's right, with 2.76 rear gears, the only time the 4bbl is needed, is from 33 to 44 mph, in first gear. How often are you in that zone at WOT? Is the buy-in worth it to you?