Having done a couple of Cavalier racks, there are a few things you want to look into.

As far as design, the Mopar (Plymouth, Dodge, Desoto, & Chrysler) front suspension was pretty much unchanged between 1939 and 1953. Most info available for the 46-48 will apply to your car (there is a lot of info concerning the 46-48 available.)

1) I used an 80s V8 Mopar power steering pump, the pump pressure is a little high for the rack and at highway speeds, the car tended to be a bit touchy on steering. Some kind of pressure reduction or by pass would help a bunch.
2) The Cavalier rack uses a center mount inner tie rod connection point. If you make a simple center link to attach to your existing original tie rod ends, at their original mounting position, it will eliminate a lot of challenges. Tie rod ends for your Dodge are the same ends as used in the 73-93 Dodge trucks.
3) The rack tends to make a longer turning radius then the original car had. You can move the mounting holes on the steering arms closer to the spindle (drill & ream the tapered holes) or you can learn to live with it. If you have not driven the car, you probably won't know the difference, but if you have driven the car, you will notice a difference.
4) When you change to the rack, it would be a good time to update to a modern steering column as well. Other wise, you will be dealing with modifying the original column in addition to running new steering connections to the rack.


There is a lot of info concerning rack conversions over on the www.jalopyjournal.com HAMB board, do a search for 46-48 Plymouth steering. There used to be a bunch of stuff here, but I believe most of it has dropped off and is gone. Gene