proportioning valve?

hi Guys, i'm just about finished my 383 Barracuda swap, but i'm having a brake problem. i got the car with a new master cylinder and power booster to fit a 1974 dart, the same as my K-frame and disks brakes that were on the car when i bought it. i also got a seperate proportioning valve (not sure if its from 1967 barracuda or 1974 dart). now i put on new hoses, calipers, pads, drums and shoes, and have everything bled (no air), but the the pedal goes to 2" from the floor and locks the rear brakes. if i put hose clamps on the front 2 lines to the calipers, the pedal only goes down 1", with the clamps off, back to the 2" off the floor. the front 2 calipers are putting out straight fluid, no air. here's my question, is this what would happen if the proportioning valve was the original 1967 Barracuda 4 drum valve, and not the 1974 dart 2 drum- 2 caliper valve, in other words, i'm not getting the correct proportion of fluid ( volume) to lock the calipers sooner. thanks for your help Gerry