I have been looking at installing a dual master on my 49 ad and read about several people with clearance issues so I looked a little more and found that a '64 '65 cadillac master is 1" bore and the outlets are on the other side. (frame side) 1/2 x 20. I also believe it has residual valves. Anyone else ever used this unit? Can anyone confirm it has residule valves? Kiethfielder, maybe this would give you enough room.
