Eberg suggested in his Mopar Action articles to iirc toss the factory one & add an adjustable one in the rear line & I went with that but a guy here said this would cause the fronts to wear excessively(which makes sense) because the fronts(discs) are going to hit before the drum linings are even in contact) & (for an A body) to use a M body proportioning valve(2 different M ones available). When it's right should a person jamb on the brakes & have 4 equal patches of rubber???