Monitor your fuel pressure at the carb inlet. Quadrajets work best at 4 3/4 psi. More pressure than that can override the needle and seat and allow the fuel pump to blow raw fuel into the intake manifold, which does little for tuning or mileage. Tee off at the carb inlet and run a line up to the cowl, in front of the windshield. Mount a 0-15 psi mechanical fuel pressure gauge on the cowl so you can see it through the windshield while you drive. It will only need to be mounted temporarily while you get the fuel pressure under control, so tie wraps and duct tape are ok. If you find you need to lower pressure, purchase a quality pressure regulator and mount it permanently in a place where it will be protected from engine heat and rocks thrown up from the pavement.

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