Make sure your adjustment between the master cyl. and booster is correct. To long, you have brake drag and to short, to much pedal drop. Put a vacuun gauge on your intake, start rod up and get a reading. Depress brake pedal and you should see a momentary drop in vacuum. If vacuum remains low with depressed pedal then booster is leaking. I have the same setup and had the same problems. Finally took Hotrod Lincoln's advice and gravity bleed the front. This means I jacked up the rear on six ton jackstands to get the MC higher than the front bleed screws. Good luck
