I bought the bracket from ChevyDuty, though I learned soon afterward that the same part was available cheaper from Classic Performance.
I converted to front disks at the same time, and used a power brake master from a '73 Chevelle, but without the booster.
I had some trouble with the brake and clutch pedals, but solved it by spacing the brake pivot a little further from the clutch pedal. At first I didn't like the solution, but now almost three years and 10,000 miles later I'm satisfied it did the job.
