Start with the spark plugs, see if they're looking fouled or are showing a lean condition. Also verify ignition timing is not sticking (if have a vacuum advance, mechanical distributor). Also hook up a vacuum gauge to see if it's showing signs of a vacuum leak-if so, try Scotty's video looking for vacuum leaks using a cigar.

This is a long shot but if the fuel tank and sending unit are original the pipe may have a crack in the neck inside the tank sucking air - pull the tank and inspect

I've had a similar problem with acceleration a while ago and it seem to be fixed whenever I adjusted on the idle mixture screws, today was the first day I went more than a couple of miles at one time and everything was fine till I had lunch in town and got in the truck and it started it's hiccups

I rebuilt the whole engine took it all apart and replaced everything new carburetor new fuel filter electric ignition, I pulled the plugs and they were clean one of my spark plug wires fell apart so I replaced it and then a nut on my electronic ignition was loose so I tightened it and drove down the road hoping for the best and everything seemed fine no more problem

Not likely a head gasket since you aren't complaining of overheating or losing coolant - given its age it could be lots of things - a tear in the diaphragm of the old fuel pump, fuel filter, points and condenser if it has them, carb adjustment of floats or a carb rebuild, bad coil or ignition wires, - these would be the most common for that year of car