I call upon my wise Jeeping brothers who...have traveled the path I am about to. Before asking, I have researched the internet, gone thru some 200+ pages of past posts on this website (learned alot) and still have questions. The D30 (73 Cj5) disc brake conversion. I received my Chevy Caliper mounts via UPS Tues. I will use the 77-78 Jeep rotors. The calipers, Chevy 1/2 or 3/4 ton calipers depending on caliper piston size difference, if any. One of my questions is what master cyclinder to use ? Direct fit is nice but, modification is O.K. if it is better. This will be non-power asist and maybe in the future, rear disc also. perhaps later Jeep or Chevy truck ? I thought that those who did the conversion might have encountered "surprises" or wish they would have done something differently. In advance, I thank you all for sharing your wisdom and experence.