i have a 72 chevelle with stock front discs with a big block. I have been chasing a hard brake pedal problem for a while now. i replaced the brake booster and it almost seemed worse. I had a little low vacuum (14”) so I put an electric pump with a auxiliary tank. I can pump up the vacum and come back 24 hours later and there’s still plenty of vacuum left in the system. I am getting 22” so I can’t blame low vacuum. I replaced the master and the front and rear flexible lines. I don’t know what to do. Could I have gotten a bad booster? Should I put my old 49 year old booster back on or should I just buy another new booster? Another question is-the replacement booster I got has the Delco Moraine stamp on it. The supposed original I have has no stamps or numbers on it. Did 1972 boosters have the Delco Moraine stamps on them?