I visited a friend in OKC with an '84 245T. He says the car runs fine with a full tank of gas, but as the level gets to 3/4 full or lower, the engine quits in a left hand turn, but is OK in a right hand turn. I suspect a dead fuel tank pump; I could hear the main external pump running when the ignition was switched on but nothing else. Am I on the right track?

This is classic.
The in-tank (or "prepump") in the tank may be perfectly fine (and sound fine, and also check out normal based on amperage draw in its circuit), but the problem is really in a small, 2" long hose that connects the pump to the metal fuel line. This is about halfway up depth of the tank, and it often cracks with age (and gasoline additives like alcohol and MBTE, etc.).

When the tank is full, the hose is submerged, and there is no noticeable effect.
But when the tank approaches half-full (varying with the slope of the ground -- e.g., hills -- and on turns), the hose is uncovered, and so is that split in the hose, creating the problem of poor fuel delivery!

Solution -- the sender must be pulled out of the tank (there's an access plate, so the tank doesn't have to be dropped) -- and then replace not only the hose, but also the prepump (might as well for preventive maintenance, as you've done 3/4 of the job anyway), and the "sock" (a screen filter on the end of the prepump).

I'd check the in tank pump.
--
If you listen to the radio in Portland, OR, you may know me as "Portland's Favorite Soul Brother!"

Thanks!