Not on my 7-Litre, but I did the upgrade on my '66 Country Squire. The Squire needed the power brake booster rebuilt, so on recommendations of the gang on the old FE Forum I sent the booster to Booster Dewey to be rebuilt and asked him for the dual reservoir master cylinder too. I can't say exactly which master they sent, but I was happy, although I'll add that the pedal effort is a bit high, but I can live with it. I'll add too, my Country Squire has power drum brakes, not the power discs of the 7-Litre, so if you decide to ask them you'd have to verify they have the right master.