Quite often you wont see fuel filters on carbureted engines as being " full" of fuel as the engine is running. I dont remember the exact reason for this, but I do know its true. This is especially prevalent with the situation of the fuel filter being installed in a horizontal or near horizontal manner. Most likely since the space above the outlet is trapped air when the filter is not in a vertical manner. If you look at many photos of cars built in the 60s, youll note many Mopar products had the filter mounted just downstream of the fuel pump, somewhat behind the alternator, in a vertical manner. The point...dont presume not seeing a full filter is a fuel pump problem indicator, unless of course the filter is completely empty. It only takes a few minutes to disconnect the filter and run the engine for the 30 seconds or so needed to allow the pump output to go into a suitable container, then you can see if the pump output flow is where it needs to be. The general rule used to be if you could pump a quart of fuel in 30 seconds at an idle, the fuel pump was working fine. Mikey 62 Crown Coupe