Good morning zank,
So assuming you're talking automatics, the A500, and then the A518 OD trannys' were the transmissions Dodge went to mid '80's for OD, the A500 is used behind the 318 in the 1988 RamVan, the A518 backs up the 360 in the 1994. If they will bolt up? IDK...
Reed is the resident Dodge tranny info Guru, and would know far more than I.
There is internet info on these swaps. First thing is Flexplate, Torque converter. Plus. These are computer controlled transmissions. So I believe you'll need a switch for OD/TC lockup. Plus a modified driveshaft if the overall length is different from your 727 setup.