Look at your calipers and make sure the bleeder is on the top. they can be swapped side to side, if bleeder in on the bottom you will have an air bubble that is next to impossible to get out. Pedal to the floor is either air in the system, blown MC seal or maybe rod to mc adjustment (to long not allowing mc valves to close). Booster will not cause the pedal to go to the floor, when it fails the mechanical rod acts like regular brakes.
read this current thread too.
http://67-72chevytrucks.com/vboard/s...d.php?t=679582