so I finally got my 69 moving under its own power. pulled it out of the garage, and had practically no brakes. I replaced everything except the prop. valve. literally. I thought I bled them pretty well. I am also running a vacuum accumulation can because I have a power booster, and a lumpy cam. its showing about 12 inches. I had to push the pedal litterally to the floor to get it to stop. ( scary seeing how my driveway takes a sharp right down a steep grade right outside the garage door. should I bleed the MC and each corner again? thanks!!

Pretty clear you did not perform a "H2 60-Second Test" of the brakes. Shame on you. After any brake work, step on the brake pedal. It should be HIGH (Rule of thumb-- The brake pedal should be equal with, or just above, the level of the gas pedal when pushed with moderate effort.) and HARD (H2) and not sink while you push and hold the pedal for 60 seconds. If it's not High, not Hard, or it sinks ANY amount, you aren't done with the brake job.

Are the drum brakes properly adjusted? Discs will adjust themselves with each application, but it may take a few pumps to fill the calipers.

Did you bench-bleed the master cylinder?

Does the front of the master cylinder tilt upward? Some do, some don't. IF it tilts upward, that's a great place to trap air.

Do you have the correct master cylinder for the power booster you're using? The pushrod sticking out of the master needs to fit properly in the locating hole of the master cylinder's piston.

Are you using a front disc master cylinder on a car that has front drum brakes? Drums need a residual pressure check valve that's built into the master cylinder. A master for a car with front disc brakes won't have that.

EDIT: Just read in my Delco service manual that the residual pressure check valves were discontinued in '70 for all GM passenger cars--I guess they decided it wasn't that important.

well I did rebleed the whole system yesterday. They are fine now. I have a front disk, rear drum power set-up. the rear drums were set up by a buddy ( a ASE cert. GM guy) and we did the H@ -60 second test as you suggested.. all is well.