You might want to look into adapting a power disc/drum system from one of the Toyota, Nissan, or Mazda pickups. They use the same 6 lug bolt pattern as stovebolts, and it seems that the only fabrication needed would be figuring out a way to anchor the calipers to the original Chevy spindles.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!