My suit up engine will not stay ideling do I need a bigger carburetor or should I instill a bigger stall converter

Engine stall or RPM fluctuates at idle.

This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control

Have you replaced the fuel filter? That may be the culprit.

You'll have to figure out if it is a fuel or ignition problem.
Is the check engine light on ?

This is probably an engine using a carburetor. If it starts and idles good and dies when the accelerator is pressed it is probably the accelerator pump on the carburetor. The accelerator pump supplies the fuel to operate the engine in this transition period from idle to part throttle until the venturi effect catches up to draw the necessary fuel the engine needs to continue running at the current demanded rate of speed. If the butterflies are opened and there is not sufficient fuel squirted into the engine when larger amounts of air are in demand it starves for fuel and thus stalls.If it is fuel injected then you have other problems, but my guess is it is a carburetor version. Ford went to fuel injection in 1990. You can just purchase the power valve if needed. You don't need the complete kit. Good luck

This is purely related to a primary fault in the fuel system but the ignition also needs to be checked.
So check the fuel filter remove carburetor and check the fuel chambers and ports for dirt and clogging. Check the fuel jets and see if these are clean.'
Now check the spark plugs, the gap and the spark intensity, if not check the HT coil, the HT wires.
Now the tuning requires the attention of an expert as when you tune the engine the condition will be evident. The fuel/air mixture and the ignition timing must allow the engine to idle with even motion.
On raising of the RPM the engine must come up in power easily.
I am sure if these two setting are in order the engine must work efficietly. However is the engine has clocked more miles, then the compression ratio , the valve settings must be checked.

disconnect the catalytic converter/muffler and see if that helps. If so, you've got a plugged converter/muffler

Check the prnd indicater switch on the shift shaft on the transmission,it could cause this if it is defective.Also,if it has a lock up converter,it could be locked in,it has a four wire connector on the transmission,and you can unplug it,let the engine cool,so it will release,then try and drive the vehicle.

The torque converter clutch could be stuck, which would require transmission removal to repair.

Could be the torque converter is locking up when it should not be.
Pull the TCC fuse and try it.
or....unplug the electrical connector at the trans and try it.
Any improvement means the torque converter or its control may be the trouble.

Check for vacuum leaks at the intake and carb. base. Check your vacuum hoses and your brake booster hose. While running, spray WD-40 along the intake and see if the idle changes. Do the same with the carb. and visually check all your hoses for cracks or breaks.