trans compatibility?
 

hi, i have a 4r100 in my e350 psd and want to make it 4x4, i have a 95 that was behind a 5.8, so its 31 spline and will take any older t case, i also have an 02 with a 5.4 that has a 271 case,
the question is can i gut and use either of the extensions and tail shafts? should i go with the 31 spline and then use a 205 or 1356 case or got with the ither 4r100 and 271 case? i think the 205 would be shorter but heavier and need the extra torque brace like the 70s trucks a bonus is i can dual shifter the t case for a 2wd low range, it might not need the fuel tank to be cut down

my second option is bolting an adapter plate to the 01 and using a zf5, i have a couple laying around? zf6s are still pricey here

Anyone??