rear disc....

[1charger69]

upgraded last year to front disc...everything set great..... .santa brought me rear discs.....my question is what adjustment is typically made to the prop valve from where i have it set w the drums?

[Kern Dog]

Only YOU will know...every setup is different. Tire height, pressure, tread compound, traction, suspension...front/rear weight bias, type of master cylinder (Must be 4 wheel disc compatible)
Set the valve closed and test it, opening it up slightly, over and over until you get the REAR wheels to skid...then close it back up slightly.

[will]

After talking with doctor diff, I have the normal 4 wheel drum prop valve in there. I bought the master from him and have no complaints. The pressure will equalize at all four wheels as the brakes are applied. I had the throttle valve in there, but it's not necessary. I don't know what setup the big guy brought you, but I have SSBC all the way around. The parking brake must be applied to keep the rear pads in adjustment on this setup.

[303 Mopar]

Don't you need a new prop valve to adjust the front pressure more so the rears won't lock up?

[will]

That hasn't been a problem for me, and I am a spirited driver, although I don't drive while consuming them.

[metallicareload99]

Don't you need a new prop valve to adjust the front pressure more so the rears won't lock up?

That hasn't been a problem for me, and I am a spirited driver, although I don't drive while consuming them.

I have 4 wheel discs also with a adjustable proportioning valve to the rear, but I left it wide open and haven't needed to adjust it down. I do have 305 rear tires though

[Kern Dog]

Don't you need a new prop valve to adjust the front pressure more so the rears won't lock up?

In a 4 wheel drum or a 4 wheel disc system, the size of the wheel cylinders or caliper bore establishes the proportioning. The fronts get a bigger wheel cylinder or caliper.
Disc/drum systems are different because the way that they energize is different. Discs are linear. Drums are progressive where 2X the foot pressure may equal 4X the stopping force.