Also vacuum. Sounds like you have a bigger cam and lower vacuum. PB work best with 18+ vacuum. Anything over 10 or 12 is usually enough for putting around but max assist needs more vacuum. One test would be to get up to speed and downshift so the engine is spinning>2000 RPM with throttle closed. At that point it should be making good vacuum. Are the brakes noticeably better?
At speed, the brakes work fantastic. While rolling along at parking lot speeds, they are not good. I'm sure is related to engine vacuum. It is exactly because of this that I am still curious as to how I could make a manual brake combination work.
