1970 brake issue. Bad booster or?

Still trying to figure out what's going on with the brakes.
Got the car out of storage last spring. Did new wheel cylinders and shoes in the rear. Also replaced the rear flex line.
Replaced front flex lines
Have good clean fluid supply to all four corners
Bled breaks, all air seemed to be eliminated from system. Great pedal feel with the car off. Start the car, pedal goes to the floor. Brake light comes on
Pulled Master Cylinder, found it to be leaking. Replaced Master cylinder, bench bled and installed. Bled brakes, great pedal with car off. Start the car and pedal goes to the floor. Brake light comes on
Bench bled master again, this time on the car. Pumped for a while, I'm confident the air is out of the master
After reconnecting brake lines to master I have great pedal feel. Start the car and pedal goes way past the spec travel distance but doesn't feel like it hit the floor, I didn't try to force it to the floor. No brake light.
With the car running, the brakes are bad. Pedal is soft, will not pump up and give firm feel when car is running, but will pump up enough to get the brake light to go out. Stop pumping, all pressure is lost and pedal will go to floor
With car off, brakes feel great


The check valve is good.
I set the master cylinder push rod free play to .010 with a feeler gauge, not be eye lol

Anyone got any tips?
Still air in the system or a bad booster?

Disc front, drum rear. Bendix Booster.
I have taken all the slack out of the rear shoes
The booster is still connected to the original vacuum source and I did verify the check valve is working
When pumping the brakes, I can hear and feel an air leak between the master cylinder and the booster

Brakes were working last fall, just not well. Replaced rear brakes, front and rear flex lines and master cylinder only. Now I have no brakes LOL

Thank you for the help.

Car is back together and on the road
The Master Cylinder failed and leaked brake fluid into the booster. Had the brake booster rebuilt by Power Brake Booster Exchange (formally Booster Dewey) They did a great job. Took about two weeks from the time I shipped it out until I got it back. Their communication was great for the entire process. Would recommend
Had the Master rebuilt by Apple Hydraulics. This experience was ok, I guess?
Took them three weeks to get the job done, when I got it back, it leaked during bench bleeding. Had to send it back again, waited another 2+ weeks. Warranty jobs receive no priority and emails go unanswered. Phone calls are 50-50 that someone will answer and if you get voicemail, forget it, they won't be calling back

Once everything was back together, the brakes still sucked. Adjusted the rod out until the brakes started to drag then shortened it by about 1 turn and they worked great.

Yes, master cyl push rod.
It took me quite a few tries to finally get good pedal feel