I did this on my 51 Panel. No axle swap was necessary. The decisions needing to be made
include where do you want the master cylinder and booster? In my case I wanted it on the firewall. This necessitated installation of a hanging
pedal brace to eliminate the floor pedals; due to Buick 455 engine and T400 trans. Firewall mount made exhaust a breeze & service access to the master a no brainer.

The kit from CPP included the front axle spindle races to convert from
ball to roller bearing. The rotors, calipers, bearings, etc. are basically from late 70's Camaros; replacements are easy. The only real custom piece is the caliper mounting brackets. The whole thing was pretty easy and combined with the power steering conversion, & tie rod upgrade, it made that old truck drive like a new Caddy!

If you are not swapping engines.. then the under floor replacement for the stock one is just fine; but, as previously stated…...the axle does not need to be replaced.

hope this helps.
mike