I would suggest since you need to retain the clutch set-up,that just removing the residual valve from the "brake side" of the stock master cylinder,then plumbing the frt. brakes from the tee forward with 3/16"line, may be a solution. As Fla54Chevy3100 has said,Non-power disc have a great feel and work good. I realize that going Dual line master cylinder is by far safer in the event of master cylinder failure but I put many,many miles on my 54' single line master cylinder with disc/drum combo brakes.You might also want to plumb in a pressure regulator valve on the rear brakes.
