Proportioning valve?

[74@scamp]

More brake questions. 74 plymouth scamp with disc brakes in front and 8 1/4 11 inch drums in the rear. I need a proportioning valve but I haven't found one on AMD or Classic Industries. Anybody know where to find one?

 

[66Valiant528]

Dr Diff? 11 inch rears on an A body?

 

[slantsixdan]

Assume you're asking about an adjustable valve and not a stock-type valve, in which case y'might get a better result without having to buy or faff around with a prop valve, this way.

 

[Professor Fate]

Dr. Diff has both adjustable and factory-style prop valves.
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Yes everybody, some A body 8.25 rears came through with 11" brakes. I've got 2 of them. Scuttlebutt has it that the factory would substitute 11" when the line ran out of 10" brake assemblies. You won't find that in any parts catalog.

 

[AJ/FormS]

If yur running big tires on the back, you may not require a valve.
I have a 68 Barracuda with
KH discs on the front with 235/60-14s, AND
On the back are 10"drums and 295/50-15s.
With no P-valve. I also ran this with 275s and no valve.
This is by far, the best stopping car that I've ever owned.

I did however downsize the rear wheel cylinders, one size.
But I can't recall where I ended at.

I also installed braided lines on the front. Holy cow what a difference that made.
And yes, I do run a booster, one off an F-body or a 73 Dart; I forget which. Works great!

 

[Kendog 170]

Years ago, I ran 74 Disc up front with 11" rear with 1974 factory Proportioning valve with no issues. I like the idea of downsizing the wheel cylinders though. I am now running the same 11" drums on my Hardtop with Willwood disc brake up front with a 68 proportioning valve.
Maybe just add an adjustable in line on the rears if you need to.