Excessive Pedal Travel

[MonzaRacer]

I have a '94 Ranger race truck that I am building and have converted it to 4 wheel disc brakes. I installed 12" discs and dual piston calipers on the front and '95 Mustang 10.5" discs on the rear. (In place of 9" rear drums and single piston 10.5" front discs.) My problem is that my brake pedal travel seems excessive now. It is about 1/3 to 1/2 travel before the brakes "engage", but as soon as they do it stops very quickly. I have read that residual valves can be used to cure this on vehicles where the brake MC is low mounted in the chassis and brake bleedback is a concern. My question is, would 2lb residual valves front and rear help with my problem even though the MC is in the stock position? Also, I believe that my MC is large enough to handle the setup as it has a 1" bore. Any suggestions would be appreciated.

Well is there much difference in Mustang to ranger master cylinder? Some of the Fords ran stepped MC. also do you have an adj prop valve in rear line?
and yes 2 lb checks are used to keep pedal travel to a minimum on disc setups, 10 lbs are used on rear drums.
Also the Ranger master if NOT a stepped bore may be too large and you may need to drop bore size as in from 1 in to 7/8in, what this does is allow the pedal stroke to raise pressure faster.
See disc brakes operate on pressure, not volume, drum breaks run less pressure but depend on volume over pressure as they have to move more.
and by moving figure it this way, disc only have to move a few thousandths, drums may have up to .100" or nearly 1/8th in, but then this also means drum brakes need adjusted but then you get idea.