I think your problem is that one of your real wheels is thinner than the other and off to one side.

IMO

Both mastercylinder bores should be the same size as originally it was a diagonal split.

I would suggest that perhaps your master cylinder is defective OR you have air trapped, try a seriously good bleed. Using my new master cylinder i had to depress the brake pedal over night to release trapped air.

Im using RS turbo front callipers with with cosworth disks and standard rear drums, all compensator have been removed and replaced with new lines and a willwood bias valve.

My valve is adjusted to around the middle at the moment and all is well.

You can try swapping the MC connections over but im not convinced it will help you, if EVERY thing else fails you could always fit the inline compensator's and your willwood bias but i think you have an obvious problem somewhere.

Rob,