While my 87 TII was running I experienced a very bad fuel cut and it was 100% repeatable... though there were criteria that had to be met.

The car has a Walbro 255lph pump, new sock, new filter and new fuel cut defender.

Any hard left turn, think drifting, with less than 1/2 tank of gas and the engine would cut, or stop revving; enough to stop the drift. If the car has more than 1/2 tank, this is not an issue and does not happen.

I've noticed the fuel pump is behind the driver (on the left of the car), so I'm assuming the fuel is sloshing away from the pump... but surely there's some baffle in the tank to prevent this, right? Anyone have any input?

 

Hard left fuel delivery problems normally indicate a clogged fuel sock. Are 1000% sure that it has been either cleaned with Acetone or replaced?

If you really are sure, and the pump pick up and sock is at the lowest position it could possibly be, then I would look at the condition of the fuel tank baffles.

 

The car suffered from this problem before the Walbro was installed. The Walbro came with a new sock and new fuel line was used from the pump to the lines. I put about 2,000 miles on the car with the Walbro, and always had the cut...

I have to admit, I'm not certain on the condition of the fuel tank.

When you say the lowest position possible, what are you after?
The OEM pump was removed and Walbro installed in it's place... with no fubar'ing of any sort.