Anyone ever eliminate the prop valve?

Some interesting and helpful replies!
I'm not interested in a brake warning switch or the light. When the pedal softens up, thats enough warning for me.
The car is actually a 70 Charger. I have posted about my brake problems on several forums, but THIS is the only time I have seen anyone address the issue of modifying the combination/proportion valve. This is a great idea since I have a few spares to work with.
The specs: 12" Cordoba discs, 2.75 piston iron calipers spec'd for an 81 Diplomat. 10.7" rear disc kit from Dr Diff. Rear calipers have 1.5" pistons. 15/16" aluminum NON power disc/disc master cylinder with a drum/drum combo valve. Prior to Feb of this year, I had a power booster with a disc/drum master from a 75 Dart. I only changed to manual because my low idle vacuum made slow speed stops difficult.
The pedal feel is great: it gets firmer the closer it gets to the floor. Its just that the feel of the pedal isn't equal to what happens at the calipers. I cant get the front tires to skid at all. I had to stand on the pedal to get the rears to skid. I have always believed that the brakes are the most effective the moment BEFORE they lock up. If i can't get them to lock, I MUST have a "low pressure" situation, at least at the front. I've considered buying a guage to test the pressure at the caliper, but I'd also need to know what the pressure SHOULD be.
I might try these mods to the combo valve. The price is right!

Okay... with the proportioning spring removed, would this mean that the front AND rear would then get equal pressure? What happens with the vertical sliding "barbell" that sits between the front and rear chambers? Does that stay in place? I would think so, since without it, it could be a step back to the 'pre 1967 ONE pot theory.

I appreciate any and all suggestions. I'm just about ready to put the power brakes back on!