I'd like to convert to disc brakes. What spindle will work for this, also any other advice would be appreciated.

 

Don't bother unless the parts are stock transplants. A lot of times the companies that make aftermarket changeover kits stay in business a few years and then you're back to square one as far as finding new rotors or brake pads that fit from a defunct company. Fairlane and galaxies had a lot in common and I know the Galaxie ran well into the seventies when they all began getting front disk brakes. A Hollander manual would help tell you which newer parts might cross over- if you knew who had one and what you're looking to do (which obviously you know what you want to do). In the end you may be stuck with an aftermarket company - just check into how many years they've spent in business and you should be safe.