The only advantage of putting a dual cylinder MC in an otherwise stock '59 is safety. If there was a failure of a brakeline or wheel cylinder in a single MC, you have no brakes. Same failure with a dual MC you still have 2 brakes working. Do not know from experience, but I have heard, that there is interference with the 3 speed linkage and/or parking brake linkage using the standard dual MC/booster that is sold out there.
Good luck,
Steve O
