[Cris]

Once you start getting away from the stock brake systems you have to pay attention to master cylinder bore size and caliper piston size. These will determine your braking pressures.

On the master, the smaller bore size will give you more "leverage" and pressure for a given pedal force, but you don't get something for nothing. The smaller bore requires you to push the pedal further.

My 63 is still all manual drums and it is easy to apply enough pressure to lock the brakes. I'm not a proponent that disks make a truck stop faster. Drums will stop the truck just as fast. More important for braking distance will be the grip of your tires.

Disk brakes shine because they can cool better under extreme conditions (towing and racing). They are also lighter, and simpler in operation.