float level too high in the carb
carb leak around the butterfly pivot point
leaky seal on the gas tank fuel float sensor, assuming the tank is inside the cab
exhaust manifold leak
other exhaust system leak
that's all i can think of right now.
tony
Overland Blue, 1953 GMC 1/2T, 100-22, 228/1bbl, 4sp/4.10 6v, shortbed/fender side/5-window.
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