I converted to manual brakes last summer. My trial and error method resulted in a caliper/master cylinder combination giving me good brakes but quite a few left over parts. I believe the unit in the red and black box was a 24mm bore master and the other is a 15/16 bore master. I'm thinking $40 for both plus shipping. Also have a few sets of brake calipers. Nothing fancy, just various GM calipers. Maybe mid 80's S-10 or Malibu. Non-metric what ever they are. They are currently in storage. Will provide picture and price if some one is interested. These may or may not work for some ones elses setup but if you have these to try you'll know witch way to go and save yourself several trips to the parts store.