There are so many things that can cause your problems. You need some help to walk you thru them.
Moderator: Please move this to 'classic tech' so we can help better.
First, do a compression check of all the cylinders so we know if they are breathing well and hold pressure.
2nd, look for a massive vacuum leak at the carb, hoses, and anything using vacuum from the engine.
3rd, verify the choke on the carb is working properly, cold and hot.
It could also be bad coil, timing, lack of fuel, blocked exhaust, or something in the intake.
1968, hardtop, 289, C4, seafoam green.
1966, hardtop, 289, original 3 speed, on the road and fun to drive.
1968, hardtop, 200, 3 speed, in work.