Is there a tranny or a kit that will adapt a overdrive automatic to a 225? Im not worried about clearring any crossmembers or firewalls and I dont care if it isn't a mopar tranny.
The easiest way is the Gear Vendors solution, mentioned above... it just replaces the tailshaft of your A904/727 with one with OD, and is controlled with a button. But it's probably almost $3k to your door...
you could adapt a a500/518 with some sl6->LA adapter plates, but you will have to do some major modification to the floor, get crafty with linkages, speedo, driveshaft. etc....