It's installed in a 68 Coup with a 289, with a very mild cam. The manufacturer (A big name in the industry whose name will remain unmentioned) said I need at least 15" of vacuum. I'm at 4000 ft elevation, 15" of vacuum in drive is not going to happen. Even under deceleration which increases vacuum to well over 25" the brakes still lack assist. I have 4 piston Kelsey Hays calipers in front, all new brake components in back and all new lines and hoses. I'm considering installing a factory replacement booster, but I can't stand how close the MC ends up to the shock tower. I was mainly looking to see if anyone else has had the same dissatisfaction as I have, and what they did to remedy it.
