'39 chevy, business coupe steering box

I'm looking for a steering box for my 39 chevy Master 85 coupe. My front (straight) axle wore out until the king pins were loose in the axle. So, I replaced it with a Jegs 4" drop straight axle with the Mustang brakes, etc. and the Chevy bolt pattern. The steering box was pretty worn so I put in all new bushings, bearings, and races. I've tried everything and can't get it to NOT develop the "wobble" when I hit a bump at more than 40 MPH. So, I bought a reversed Corvair box. The hot-rod shop I took it to put the new Corvair box tells me the geometry will be wrong. I told them not to start on anything.
S0...…………….does anyone know where I could find an original box. I've adjusted it every way the original book tells me to. I think the worm might be just worn out.
Thanks for listening.
Copco

 

I went to Ebay and started buying NOS parts for my '40 Chevrolet steering box. It didn't take long to get all the parts needed to build a NOS box. Mine drives as good any car on the road.

Does yours use one of these? https://www.ebay.com/itm/1939-Chevr...W5bbicu:sc:ShippingMethodStandard!64086!US!-1
I hear they can cause all kinds of problems with the steering. I just checked e-bay and found a couple pitman shafts and one worm shaft that could work.
I also replaced the ball and socket tie-rod ends with the newer, sealed type, that made a difference since the balls and sockets were worn on mine.

 

Did it wobble before the axle swap?

 

you might try a steering stabilizer ? done it -it works -try "pete N jakes " very reasonable !

 

In my opinion, you don't have enough caster.