The 37 to 41 (round back) spindles are a direct fit on model A thru 48 axles. The 42 thru 48 square backs will work too and you can bolt Ford/Lockheed or 39 Lincoln/Bendix brakes right on either type.
Steering arms will most likely have to be bent down to get the tie rod under the wishbone if the axle isn't dropped. If it is dropped, you'll probably have to ream the taper in the steering arm on top to allow the tie rod to go above the wishbone.
Why? If you are trying to add early Ford brakes there is a low cost (about $30) kit available. There may be a problem with some of the disc brake conversions, but again why are you trying to do this?
On the 11 inch and smaller drums, there are clearance problems with the top of the later spindle types but they can be whittled down to fit the wheel cylinders.