I'm trying so hard to figure out the fuel supply problem in my rear carb! I don't see any fuel coming out of the accelorator pump nozzle. I have already found that it is not a stuck needle & seat problem (where the float is). I changed my fuel filter. My car is stalling out if it is under load. The only thing that keeps it going when I start it is the fast idle choke when the car is warming up. I also blew on the opening where the fuel initially comes into the rear carb and forces the needle down. there is no blockage there. The jet is clear and there is fuel in the area where the float sits! I just had these carbs completely rebuilt! I also have diagnosed that it is not a problem with the dwell setting in the distributor and all of the spark plugs are good. My timing is fine as well. I'm so confused!