KH disk front 83/4 rear, prop valve and master cylinder brake line question

You can't go wrong using stock (pick a year) parts. Like choose 67 or 69 depending on the rear end backing plates if A body. And when you go to the store order all the parts based on the year dart, for example.

Years down the road you will be glad you did.

As for the way you have it plumbed now you don't need the 70 something distro/proportioning/brake warning block.

You have the rear most cylinder going to the front brakes, the front most cyl going to the rear brakes with a proportioning valve in that line.

I would get a 67 to 70 disk drum master cyl.

The 1- 1/32 bore is 0.031 over the stock 1" bore. As mentioned slightly more leg force.

15/16 is 0.0625" smaller requiring less force but more travel.

Personally I wonder how many 1" bore MCs have been rebuilt so many times that they are 0.030 over from the rebuilder.

I did some quick calculations and with the assumption that with all other things being the same....

Compared to stock 1" dia mc...

1-1/32 would increase leg force by 6%

15/16 would decrease leg force by 14 %
If with 1" mc you press with 500 lbs...

1-1/32 it increases to 530 lbs
15/16 it decreases to 431 lbs


As for smaller rear wheel cylinder. To me that just complicated things and we don't know if the op is using 10x 1.75 or 10x 2 or 10x2.5 or 11x3 rear brakes.

So an adjustable valve (which he already has) would be IMHO the right way to go