1969 Chevy C10 Brake Issues!!!

Story- 2 Years ago I Restored my 1969 Chevy C10, used CPP Front Brake Disc Conversion Kit. Installed new rubber hoses, Installed 1971-1972 Power Brake Booster and Master Cyl brand new. Installed CPP Proportioning valve, rebuilt rear brakes: new wheel cylinders and new rear brake hose.
Problem- I only have front brakes. Initially when I set it up I routed the lines from the Master Cyl wrong and had them reversed, after bleeding the brakes many many times I only had rear brakes, test drove it and confirmed this. (Any touch of the brakes and the rears would lock instantly with no front)
So I re-routed the linees from the MC to the Prop valve the exact opposite happened only front brakes. It's been like this for the last 2 years..... HELP! What's wrong here? I've used over 1.5 gallons of brake fluid over the last 2 years bleeding brakes on this thing! I can reset the prop valve but it will never stay centered and never has?