Ramblin_Stew:
Sounds like a nice rig you have. Before doing the disc brake conversion, you might consider converting your four-wheel drum brake system to power brakes. I have done this conversion with a factory power brake booster on several '64-'66 trucks with great success. The pedal is much more responsive, with substantially less mash.
I see the complete factory power brake boosters on eBay quite frequently. If you go that route, make sure you get the entire assembly, including the push rod and aluminum wedge that attaches the booster to the firewall.
Good luck with your brake situation.
