factory power steering is hard to find and usually expensive when you do. if you want it to ride, steer and stop well, do a MII front suspension.
...there is no later model power box that works with these cars. if there were, 10 different manufacturers would be selling kits to install one.
Repair or replace worn parts in the front end and get an alignment. You will be surprised how easy it steers once you fix 60 years of wear and neglect. If you use radial tires use narrow ones and pump them up to 32PSI. A friend of mine who owned a 52 Chev did this and it took away all desire to add power steering or do a clip. Saved him a lot of time and money too.
I had the chance to buy a 53/4 p/s system cheap years ago and should have done it along with other nice options that were in the cars at a old yard I got parts out of.
Several options for electric power steering. Flaming River, HHR, Chev Cobalt, to name a few. ALL WILL WORK WITH ANY BOX.
there is a stock set up for sale on the Facebook group Kustom 49-54 Chevys https://www.facebook.com/groups/1571626872978479/
My 50 Fleetline has this Ford power steering setup fabricated, installed by a previous owner, seems to steer fine and clears the small block that is currently installed, running a GM power steering pump.
Like Squirrel said, and I think somebody makes a needle bearing washer setup for these that makes them a little easier to steer with the stock stuff.