You could get rid of ABS by removing the unit and stock MC then by swapping in a 1" bore MC from a 4Runner, unless the stock MC has only two ports on it. Bend up lines to each axle and lines to each caliper...done. Then the braking system would be really similar to a 60/4runner/t100 with disk brakes out back. If you need to, you can put in a proportioning valve for the rear circuit.
The 80 MC bolt pattern is the same as the 60/4runner, right? I bet it is.
The 80 MC bolt pattern is the same as the 60/4runner, right? I bet it is.