You know what they say, if it ain't broke don't fix it! If I read that right you have 4 wheel disc now? I'm assuming you bench bled the m/c and there is no air in the system. If you pump the brakes do you have a pedal then? I would check to see if the rod in the booster is correct or adjusted right if it is adjustable. I'd call Wilwood and ask them if you have the right m/c . I know on hot rods they have residual valves in the line to keep some pressure on. Converting things never seem to go smooth!