How it runs

Check your ignition stuff first like timing etc. Then check the carb sounds like your accelerator pump is shot which would mean time for an overhaul on the carb. Lot of alcohol in todays fuel so it wears carbs out. Especially older ones. If this truck has been modified though then this is not really the correct diagnosis.

It still could be but it might work with adjusting the accelerator pump more but it also depends on what cam I sin the thing to to big a cam will cause that an d what size carb is on it. 750 cfm carb is optimum size for that engine

Carter went out of business many years ago but the competition series were three different types afb avs and hell ican't remember the name of it lol. It hasd a bakelight bowl an dloked very similar to a Rochester 4 barrel it was 850 and 1000 cfms. If it's the 100 it's way to big. It cold still be an overhaul as well though

Well you need to know what your timing is you may have to bump the timing up to 12 degrees initial then go from there due to spark knock. Check the stuff out on line for your carb they maybe tell you how to adjust acc pump, metering rods, etc. Your rods may be to small as well. When you modify these motors you just can't throw stuff on it and expect it to run right it takes tinkering here and there to perform.

I can't fix it for you I have given you everything I can think of