Old vacuum gauges usually have a pressure side to them for checking fuel pumps. Just "T" it in line right at the carb inlet and run the hose out so you can see the gauge while driving. Hold it down with the windshield wiper, don't run it in the cab! Any good pump should hold 2 1/2 to 5 psi and up to 6 or 7 at idle. Glass bowl filters are kind of deceiving, they can have fuel in them but its not going anywhere.
Joe
