My '71 challenger with a 10/70 SBD has a black painted booster and master cylinder, but the car was restored prior to my buying it and I'm convinced those are wrong. I believe my car should have a plated Midland Ross like shown above, and my master cylinder is the correct one but I think it should be gray phosphate coated not painted black. That gray phosphate looks a little like bare cast iron but isn't, it's coated.