So i'm guessing this scenario isn't correct. My brake pedal feels extremly stiif, very little pedal feel. It takes a big push on the pedal to get the car to slow down. Brakes can still lock up but i'd like to have a softer feel better modulation but with good power.

My setup has a 19mm MC, Braided lines, Front "A" calipers off a 76 911 turbo with vented rotors, Rear brakes are "M" calipers off an 84 Carrera with vented rotors, plus a bias valve set all the way to the rear.

I'm planning to change the rotors & pads. Grooved rotors & Hawk or Mintex pads. Plus flush the system with ATE.

Q, is there something intrinsically wrong with my setup, will it ever give me good feel without the need for herculean thighs?

i had a very similar setup on my car - except with widened stock 914.6 calipers rear - and a 23mm MC. i didn't find the pedal pressure excessive. things to try - could be your disks are rusty or your pads glazed - or both. do a piston surface computation - i bet full rear bias isn't what you want...

BTW - '76 911 Turbo Carrera came with the aluminum 'S' calipers - the 'A' is the same caliper in cast iron, but '76 Turbos didn't use them ...

Non-servo brakes do take some getting used to for people who've grown up driving nothing but cars with power brakes. Sounds to me like your system is in good shape. If you'd like a softer pedal, you could try a 17mm MC (i.e., stock 914), which will trade longer pedal travel for more braking power for a given amount of leg power.

If you have the bias valve set "all back", then it's going to actually be set to "no bias valve" or "even", since a prop valve effectively only limits the rears, it can't add "more" to the fronts than than rears. You might as well not have it in the system.