51, disc brake conversions are fairly simple if you keep in mind what the goal is......many people dont try to understand the basic concept so they get into an overcomplicated mode.

The rear discs are the easiest. You can find a rotor that fits your axle flange and try to build a caliper mount to position the caliper. The rotor slides on just like your brake drum does; therefore, the rotor must have the same lug pattern as the axle flange. The center hole in the rotor can be enlarged by a machine shop if necessary. The other important dimension is the positioning of the rotor faces relative to the axle housing end (where the brake backing plate used to mount). The caliper mount can fit on either the front or the back of the axle flange. There are two basic GM calipers; the GM Metric calipers have a smaller pad area so are better suited for lighter cars. For your truck, go with the full sized calipers. Rebuilt calipers are cheap, dont scrimp by using junkyard crap. You can even buy brand new repro calipers for less than $100 each. Your biggest challenge is building the caliper bracket to position the pistion side of the caliper relative to the rotor. Choosing the right rotor can make the caliper bracket fabrication easy. For six lug applications we have used the Raybestos 5977 rotors from a 96ish Chevy truck front....Raybestos also sells the same rotor with 105977 tag for less than $30 brand new (the 10 prefix is their cheapie line built in China using old military scrap that we shot in WWII). There is an equivalent Raybestos five lug rotor.....probably for the same Chevy truck (I have two but they dont have a number stamped on the rim). We have used these rotors on Dana 60 rears, on a Toyota Land Cruiser rear and on a Camaro rear.

For the front, the challenge is how to mount the new hub to the spindle OR how to mount the new rotor to the hub. A new rotor to the hub is the easiiest since the wheel bearings fit the hub/spindle combo. do some Google research since someone has done this (assuming you have Ferd truck spindles) If you have Cad front spindles,....well, you're home free since front discs were available on the Cad.

Use a disc/disc master cylinder and power brakes. Go to http://911brakes.com/ and read up on pedal ratios and master cylinder sizes. Make sure you do have a disc/disc master cylinder...and get a new one. For line sizes, 3/16 works great.

This is all that I can fit in the message length.

mike in tucson