power brake booster system a-body

Do you think the issue was the cam size and needing to use the extra vacuum assist? What cam grind were/are you running? What engine displacement? I'm building a 340 for my 67 Barracuda.
No the cam has significant lift as well as special rocker arms with added opening. The brakes just about put me through the windshield when they worked. But the only way I got them to work was to have the peddle real close to the floor. This had been the same issue with the original brakes. And another kit I had. Now I am running a hydraulic system and it allows my peddle to be in the right place. I have a drum/drum single master cylinder car with a 225 Slant Six. Though I have it set up with duel carbs, duel headers 10:1 compression

A number of years ago I added disc brakes off a Duster including the booster. That is when my problems started. I believe I had the wrong peddle rod going into the booster.

It is a 8" duel diaphragm booster with a Chevy duel master. I also have a new one off the barracuda I will though in. It is the 4-bolt type. The new master that goes with this is a two bolt.

If you go to master power brakes you can see the kit I have.