Cab, I think you're about right on the secs/gal; I seem to recall that 20 secs/gal is good for a low-10-sec car.
Fig, take a really good look at your spark plugs & check your float settings, and if there's any rubber hose in the system, make sure there aren't any internal cuts that can create a flap inside the hose that reduces the amount of fuel it can flow. If you're running a stock pickup, make sure the fuel isn't pulling away from it; on my Roadrunner, I added a length of suitable hose that lays on the bottom and extends rearward a bit inside the tank. My Duster uses a sump.