Having braking issues

[69ZBFairlane]

hey there just wondering if you guys could help me out with a little advice, I own a 69 zb fairlane 500 that has the double resovoir master cylinder and the vh40 booster on the passenger side of the car,it has fornt disc and rear drum brakes on it from factory...

I have put new front rotors new front brake pads and have flushed and blown out the lines with the air compressor as it was sitting for a while with no booster in it..

Ok the problem is that when I get in the car I have to pump the brake pedal a few times to get it to firm up,then I start the car and move out the driveway and push the pedal and it goes down near the floor and doesnt slow the car very much and then I take my foot off the pedal and let it come back up and then it firms up to near the top and stops the car fine....I gravity and normally bled all the brakes put new fluid in and also bled the bleeder on the vh40 and the proportioning box on the front shockie tower and this is the best its ever been but its still not right can you please point me in the right direction any help would be at all would be awesome....thanks