changed out the master cylinder, bled the brakes and still no peddle when the car is running. If I unhook the vacuum from the booster I have good peddle as soon as I reconnect the vacuum to the booster my peddle goes to the floor. Booster problem? any ideas would be appreciated. Thnx.

 

Either you haven't got all the air out or the rod between the booster and master is too short. There's something in my head about that from when I changed the master on my 79. Was there anything in the instructions about that?
You just about have to bench bleed the master,it's very difficult to get it bled on the car.
Good luck!
Ron

 

Bench bled the master before I put it on, rebuilt 3 calipers and replaced one. Still no peddle. Yeah the instructions said to adjust the rod but the rod between the master and the booster isn't adjustable.