you are trying the wrong approach to repair a problem, before even starting to look at the carby first make sure the engine valve tappets are set and the distributor is working correctly and set correctly, make sure your spark plugs are good and the coil is not about to die.
then work the carby, your car would have the old shape carby but its still a pretty basic 2 barrel carburettor - swapping out smaller jets wont help at all. You need to correctly overhaul the carburettor or get someone to work on it who actually knows what a carburettor is