Use GM 3/4 TRE. they are 7 degree taper with 7/8 threads. bungs are easy to find and I believe ford uses the same 7 degree taper.
Then simply buy a reamer and ream your pitman to the matching taper. That's what I did when I went tons.
Also I wouldn't even think of using a stock Jeep TRE with this swap. They are way to small.
I think the part number for the TRE's are ES2010L ES2010R. Or if you need the longer shanked ones It's ES2027 or ES2034 IIRC.
1979 CJ5 408 AMC
1988 YJ 331 Stroker