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 dana 60/14b, T18, d300, PSC hydro assist, Wheelbase stretch