I don't know for certain, but I'd be surprised if the swap would be a
bolt-in.  Until '51 Champions and Commanders were essentially completely
different cars (most sheet metal, wheels, brakes, wheelbases, etc.).
Paul Johnson

Sheldon,

The Chassis and sheetmetal are not the same between the Champion and
Commander just as Paul said. You should be able to get most parts from
Studebaker International or S/A. The hardest thing to find may be wheel
cylinders, but I recommend getting the ones you have lined with Brass
or Stainless Steel that way they won't give you problems with
corrosion. White Post or Apple Hydrualics can do that. If someone
rebuilt the engine they may have not tightened one of the wedge bolts
that locks the piston pin to the rod, that would cause a knock sound.
It may be just as well to pull the motor and check it over and
reassemble it. Over all the Commander 6 is much nicer engine since it
has alot more torque than the Champ 6 anyway. It most likely will be
best and easier to fix what you have.

Good Luck