I believe I have a late model 74' 260z since a ZX Booster mounts without having to drill new holes. I read a bunch of posts and I recall installations requiring to flip the booster upside down to fit. I did that and now the last 1" of pedal travel (before it hits the brake switch) has a noticeable "stick". It sounds like a thud and feels like the boost and/or rod are getting hung up somewhere. I checked around the linkage and nothing is interfering. The rod to the booster seems to attach to the brake pedal arm easily, but it's hard to tell if it's going in straight. I'm thinking the booster needs to be re-installed in reverse to get better alignment? Or is this behavior normal? All my tests were without the engine on. Is it possible having no vacuum causes this phenomenon?