on my 66 I did, the 65 satellite and others already had an adjustable proportioning valve on them . I used all new hard lines from inline tubes and got their ($90)prop valve(going on wife's dart.). I could have used it. But the one I got on here from a 73+ unit was a whole lot cheaper(that's going on the my Dart)plus it is already biased for the drum/disc for a 73. Or you could use an adjustable valve like many people do. you should need one to adjust the bias from front to rear to keep em from locking up. some people say they didn't use a proportioning valve and have no problems yet. I'd be worried about the excess pressure going to the rears locking em up.