AC Delco Master Cylinder

[samkost]

Just a follow up on my OE style Master Cylinder swap.
With help from a friend we swapped out the OE master cylinder with the new bench bled master, checked the correct gap for the long piston between the booster and the master ( 1/16”+ gap before pedal activation), and then bled the system starting at the right rear drum, left rear drum, right front disc then the driver side disc.
After a test start up to check for leaks I took it for a test drive only to have the same previous hard pedal condition.
I could not lock up the brakes.
I did need to replace the OE master due to age and a little corrosion but now the focus is on a new faulty (less than 150 miles) POL Power Brake Booster.
I did the two pedal tests and it failed both.
I then ran the engine for a few minutes, turned it off and 30 seconds later unplugged the power booster check valve.
No hissing or escaping air at that point. Booster check valve tested good.
I then got a vacuum gauge to the carburetor vacuum line and found 16 in. Hg of vacuum. I believe and hope that this is good enough vacuum.
So after every said and done, turns out I may have a brand new faulty POL Power Brake booster. I have heard that others have had brand new bad booster issues out of the box.
I will call POL on Tuesday and see what they have to say.
I may just go with my OE original functioning black painted Delco Moraine power booster and forget the pretty Cadmium plated after market booster.
no more bling!
I enjoy working and especially learning about my truck.
Any advice and input would again be appreciated.
Thanks all,