Firewall Brake Booster Kit

[Buzz0]

I bought a 7" dual diaphragm booster/master cylinder/prop valve combo from Classic Industries under their part number PB828D. The prop valve has a CPP sticker on it, the master cylinder has CPP embossed on the sides so I'm pretty sure it is the same kit as CPP part number 5864BB4. Question 1- is this the same kit? Question 2 - what size bore is the master cylinder? I'm not getting near enough brake pressure so I have a hard pedal.

[CPPAaron]

same kit. The master is a 1" bore. Generally a hard pedal is a booster that does not have enough vacuum from the engine. All booster need 18" at idle as a minimum.

[Buzz0]

Thanks Aaron! Plenty of vacuum so I've narrowed it down to low pressure. I'm running Wilwoods on the front vs. single piston calipers, so that's probably why the system wants more pressure. I'll try a 7/8" master cylinder and see what kind of results I get. The car stops fine just have a hard pedal when I am stopped.