Single to dual master

[Wayde]

I have a 66 formula s Barracuda with factory optioned KH disc brakes on the front,I'm updating the master cylinder, including adding the distribution block for the dual port master.The original had a line running from the factory proportioning valve to service the rear brakes,looking for info on how to route the lines to plumb the new brakes.thanks for any help.update ,I should have added that I am using combo valve , master and new lines from inline tube

 

[Oldmanmopar]

This may help. The front port on the master cyl. goes to the top port of the proportioning valve. I like using this style disc brake single proportioning valve over the dual style or an adjustable for the street. They are more consistent and easier to plumb with less fittings to leak. This is just my preference.

These were used from 1970 - 1973 and are available . I use them on all conversions

I recently changed this 65 dodge over to dual with drum. Master and drum proportioning valve for drum brakes and that's all it took. Disc and drum take different valves. Adding a restrictor valve to the rear for front disc is an option . I just never use them.

 

[AJ/FormS]

Adding a restrictor valve to the rear for front disc is an option . I just never use them.

With modern wheel-cylinder kits having the cup-spreaders in them, that residual valve is more or less redundant.
OP;
make sure your port to the front system, does NOT have a residual valve in it, else the front brake pads may be dragging all the time.
and, the disc-side gets plumbed to the larger reservoir.
The front side of that Combination valve is just a splitter.
The rear side has a hold-back valve in it to delay the rear brakes.
In-between the two is a safety switch, to turn the dash-lite on if one side or the other goes down.
Don't forget to "bench-bleed" the master, before you attach the brake lines. You must get the air out of the master, else you will Not get a hard pedal.

 

[66fs]

I use a 73 Duster with Disc brakes as my model for parts. You can even get new SS brake lines that will fit perfect on your early Barracuda or Valiant. K-H or 73 discs, only the caliper soft lines change on K-H discs.

 

[67Dart273]

............That old poly B body, tho............