I'd start with verifying the gauge isn't lying about the oil pressure being low. Use a real mechanical gauge. If it really is low, I'd probably try thicker oil and see what that did for it. The next step would be a compression test, and maybe a leak down test. I guess I'd really want to know what condition the motor is in. If the compression and leak down tell you the motor is pretty sound, I'd roll in the rod & main bearings, new oil pump, and a pan gasket, and maybe that timing chain and gears.

If it fails muster on the real oil pressure test and fails on the compression test, save your money for a reman motor, and then drive this one until it retires itself. I've seen low oil pressure Ford motors run a long time without issues. Gene