Booster size and Vacuum w/ 4 wheel disc brakes?

[chr2002ca]

The Master cylinder that came with my Baer kit was a 1 1/8" bore CPP master cylinder. This was mated to an 11.5" original style Delco Moraine brake booster. Due to valve cover clearance problems on my big block, I never used the first unit and instead replaced that MC and booster with a 9" dual diaphragm brake booster which came mated with a new MC and 4-disc prop valve, all of which are made by CPP. I purchased my latest unit in person at their store after telling them about my setup. It was the one that CPP said I should use with my Baer disk brake setup and my 9" dual diaphragm brake booster. It also has a 1 1/8" bore.

So thats twice that I have received 1 1/8" bore Master Cylinder for my power disc brake setup. Are you saying that I have now been given the wrong sized master cylinder twice? That would be a bummer. Why would they sell me a MC and booster setup that wasn't capable of providing enough brake pressure to the very common brake setup that I have and described to them?

I appreciate the feedback.