1968 4 piston front disc brakes

[gt289]

A direct swap, like Mustang 10x1.75 or 10x2 to a Econoline 10x2.5 will mainly yield increased shoe
longevity. There is some increase in braking because the "wedge" is more effective.
(self-energizing "wedge"- the brake’s anchor pin acts as a brake shoe stop and prohibits the brake
shoe from its tendency to follow the movement of the rotating drum. This results in a wedging
action between the brake shoe and brake drum. This wedging action combined with
the applied brake force creates a self-multiplied brake force.)
It will be a slight difference.
For greater effect, increase the rear wheel cylinder size to 1" or 1 1/16. That'll get your attention
pretty quickly. Small changes in bore sizes = massive changes in force. (inverse square law)
The Shelby's all ran an improved rear shoe compound. Velvetouch semi-met or something like that-
large segment blocks in the shoes too to control cracking during heat cycling.
A change in Mu (coefficient of friction) like that is all that's really needed in the already light
Mustang rear end & the increase in shoe & DRUM size tends to greatly improve thermal issues.
(My wife's '68 runs the 10x2.5 stuff in the rear, 1" wheel cyls and Praise DynoBrake shoes. It's
a good match for the Boss 302 Trans Am front brakes she has.....)
If you really want the effect, use the 11" rear stuff like Cobra Automotive recommends- even
more wedge effect, etc.

[SAC69]

Thanks for the insight.  I'm about to redo my rear brakes, where could I get 1" wheel cylinders? Is there any adaptive issue if they are integrated into the existing stock setup?

[gt289]

Shouldn't be any problems. It does get interesting when you get above 1 1/16" because not
a lot of vehicles came with wheel cylinders that big that'll fit the rear backing plates in an original
manner.
I hit up Autozone for a Bendix 1" rear wheel cylinder, part number 33636, $9.99 ea plus tax.
(I think it's also Wagner F78978 and Raybestos WC37271, but don't quote me on those)
My notes are sketchy but I think '76 LTD is the application.....
Going to the 1" rear wheel cylinders gets you another 184# of force against the shoe vs the
stock 15/16" cylinder.
You may have to dial out some rear bias with a proportioning valve, that's a big jump up in force.

[SAC69]

Thanks for the good info.

[sigtauenus]

If its a SSBC kit then its the KH calipers and bracket like what was used on 65-67.  I had a kit like that on my car before I switched spindles and put single piston calipers on.