I'd recommend a № 2106R camshaft from Oregon Cam. That is Doug "Doctor Dodge" Dutra's RV10-RDP cam that improves breathing and resultant driveability on a stock or near-stock 1bbl or 2bbl engine in a driver type of car, without introducing new problems.

Also: careful CCing of the head to determine how much material to shave off the block and/or head, careful attention paid to the cylinder head in terms of smoothing out rough castings in the port and valve pocket area without going overboard. A good quality timing chain and sprocket set. A blueprinted/massaged oil pump (check with Doctor Dodge). Exhaust options previously described. HEI upgrade for the ignition, with a thoughtfully recurved distributor (get with DusterIdiot here on this board). A good 1bbl carburetor if you're sticking with a 1bbl -- I'd snag this one for your '73, if your budget allows it. The Carter BBS is a better carb design than the Holley 1920 you have now, and the truck calibration will run better than the more strangled passenger car calibration. Only minor adaptation needed to install this carb on your '73, and nothing runs like a new (not "remanufactured") carb.