Dave,
Your post about a "transfer" pump made me remember back in the '73/74 "gas crisis" when I was in the Navy working on airplane radial recip's. They had a 24V system with a motor driven "startup/backup" fuel pump to feed the massive carb - had AN24 (1.5") fittings as I recall. A guy told me that his neighbor who worked in the rebuild shop, had pirated an old motor & pump, mounted it in his trunk piped into the top of his gas tank, and put about ten feet of old fuel hose on the suction side. With a pair of batteries in series he'd cruise the neighborhoods at night, looking for cars parked at the curb, or even in a driveway. Said he could pull up next to a car with a full tank (he cruised the better neighborhoods ), stick his suction hose down the filler neck and suck the tank dry in less than two minutes Of course, I never saw this contraption, but it made a great story over morning coffee...

Sorry for the hijack