HELP!!!! Question regarding master cyl brake booster option

[erikh09]

I am currently converting my 67 GMC 3/4 ton to a 1/2 ton. The truck came with power drum brakes and I want to put discs up front. Can anyone please help lend a suggestion as to which master cylinder and booster I should use (model year) so I can go to the auto parts store rather than order from a fancy custom car shop and overpay for the same part. Also, should it be for a 3/4 ton or 1/2 ton when I spec it out to the auto parts store!! Thanks as usual for all of your help!!