You bigger problems then the T4. First the T4 was never intended for a V8, so behind a V8 your junk description is correct. Second, a Dana 30 and AMC 20 were not designed for 35s, especially with 2.73s and if you are intertaining 37s - 42s then at least Dana 60s are in your future.
The T176 or T18a may stand up to that power and they are AMC. Otherwise it is adapter time. I like the SM476 especially with a doubler (203&205). Can be found in junk yards. But the toughest trans is the T400, but you want a manual.
1985 CJ7 - total customization underway, Sublime green and Plum crazy purple, Ford 9", 258 w/ Holley 475
1985,93 CJ7,YJ - L98 TPI Vette motor, Atlas twin stick, Dana 60s front and rear, Arbs, 39.5 Swampers