My 65 dart(318/904/7&1/4) w 73 discs(76 2.70" calipers as opposed to 73-75 2.60" ones) & 10" drums on the 7&1/4, I didn't use a prop valve when I put it together & it stops fine(around town) though I have not had the displeasure of having to do a panic stop. I sold the car & I'm buying it back this weekend so I am going to check the pads/linings & see what I see