Hey all, I just got some Kelsey Hays front disk brakes for my 66 Valiant with a slant six, the question is do I now need a booster or can I just use a later disk/drum (74) master cylinder? I've tried a few searches but I just seem to get a bit confused as its done several different ways?
Anyway this is a new car for me and I've been bitten by the ABody bug! I am waiting on floor pans, then going to tackle the brakes and then maybe a 4 speed to replace the 3 on the tree? LOL dose it ever end?? any help would be greatly appreciated.

Thanks! Marty

I did find a good thread on this

http://www.forabodiesonly.com/mopar/thr ... ad.266225/

I'm not an expert on the KH disc brake system, but as far as I know you don't need a booster. I think those KH discs were available as either power or manual. You just need to make sure you get the correct front disc/rear drum master cylinder. I've been looking into this recently so the details are still sorta fresh, but if you're lucky SlantSixDan will wander into this thread and tell you exactly what you need to know.

You definitely want a master cylinder with a larger rear reservoir (which feeds the front brakes). Master cylinders with equal-size reservoirs are made for four-wheel drum systems. The only other consideration is what master cylinder bore diameter to use. A smaller bore on the MC gives you an easier pedal feel with longer travel. A larger bore gives you a firmer pedal with shorter travel. Master cylinders for power or manual systems can be used interchangeably, as far as I know.

The KH disc brakes were originally used with a 1" bore diameter MC, but you can also use a 15/16" bore (spec'd fpr 71+ power front discs but usable on manual) or a 1-1/32" bore (spec'd for 71+ manual front discs).

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

Slant6dan recommended the following (back around 2008) fitment for my '67 Dart with manual K-H front disks and 10" rear drum (a 8 3/4" rear at sometime has been installed on my car, hence 10" drums):

Master cylinder Raybestos 36412 disk-drum, and 13/16" rear wheel cylinders such was used on cop cars of the day equipped with 10", 11" & 12" rear drums to resist or prevent premature lock-up under hard braking such as raybestos 37696. You may have 9" rear brakes on your car so this info may of may not apply.

I installed Raybestos MC 36412 and prescribed smaller 13/16" rear cylinders. Pedal feel is OK, I can easily lock'em all up, but a much heaver foot is needed compared to any powered assisted system. I don't see the need to convert to a power assisted.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC