42rh transmission

If I pull a 1994 318 magnum and auto trans from a p/ u and change to carburetor, do I need some kind of computer for the transmission?

No. Toggle switches are enough to control OD and lock up. Can also get the line pressure kit to do it for you from PATC like others mentioned. OBD2 started in 1996 and brought the computer controlled transmissions with it.