4 Speed O/D???????

Ok guys... I've posted this in the general discussion but wanted to add it here also... I've come across a full size Dodge Van.. mid-80's in the local yard.. it has a 4 speed O/D transmisson in it. The shift pattern on the top of the stick has the usual 4 speed and to the right of 3rd gear it says.. O/D... any info or suggetions.. I'm thinking of grabbing it for when I remove my 6 cyl and go with a small block in my "A" body... any comments apprecated.. either here or to [email protected]

Thanks,
Bryan