I have tried it with and without vacuum, booster is definitely working. Its a disc disc setup, not sure on the booster. TCI made a power conversion kit with the brackets and new pedal assembly along with the CPP booster and master cylinder mounted on the frame.
How would I tell which booster it is? I think its the CPP 8" booster. Knowing this info where should I go from here?
I can definitely tell that the booster is helping stop the truck but its just too stiff of a pedal and I can NEVER lock up the wheels if it came down to needing to. I pinched the vacuum hose and got 2 stops until the vacuum was gone in the booster and then no more power assist.