I have the same problem. For me it was vapor lock if i sit in traffic. My thermo reads 200 and then it's time to move or pull over and wait thirty minutes. I just had my car shipped out to me after ~20yrs and the temp issue is going to be resolved!!! (I hope). I just ordered a new high flow water pump and diverter plate from Ames as well as a high torque starter (issue #2 = hot start).

If you still believe it is fuel related I would check your fuel pressure with a vac gauge before doing all that other stuff. Could be something related to the accelorator pump? Not sure what carb you have.