I've just noticed that the rear wheel cylinders on my 72 HC are different sizes on the cast block (the mounting face) and one has slots in the piston ends and one has flat ends on the pistons, i.e they are different to each other. Is this correct and if so why? They are Lockheed with manual adjusters, and I believe the Moprod numbers are MWC143 and MWC144
Thanks Marcus