I have done a disc brake swap on my 69 chevelle and the setup came out of a 1971 Chevelle and the proportioning valve is different that the one from 1969 as you know. My question is can I use a 1969 Chevelle power dic brake master cylinder with the newer style setup, or will it not work correctly. I want the look of the 69 master cylinder with the two holddown style to look more original. Has anyone done this.

the master cylinder has to be matched with the booster. there are 2 different rod lengths. if you have tthe booster from the 71, the old style mc will not fit it. if you have 68-70 booster, i am pretty sure you can do what you are saying. but to be more correct you could leave your origional block on the frame and get the correct valve for your car that mounts under the master cylinder. did i confuse you? :confused:

not sure in your case but i put 71 chevelle disk on my 66 chevelle with the 71 poportion valve and 67 master cylinder with manual brakes though every thing off of 71 was for power brakes infact i just put 72 chevelle disk on my 67 nova with the help of globle west lower ball jount adapter