Once they start smoking there is almost no "cure in a can" that you can add to fix them up. The engine is just not seating in the rings, but probably the valve guides and more.

You could try a heavier weight oil, like straight 40 to see if that helps. I have also kept cars alive with a few cans of STP in the crankcase. I know lots of mechanics will shudder at that suggestion, but I kept a Pontiac 389 alive with 3 pounds of oil pressure for a few months until I could tear it down.

The 302 swap is a natural, in fact, didn't Ford make a Mach I version or something with this engine in the MM II already?

Good luck, and welcome to the forum.

Don