power brake booster

Also keep in mind that as soon as the engine speed comes off idle, she begins to make vacuum and with a 274*/224@50 cam, and decent initial-timing, you should have plenty of vacuum, by 1200rpm. Plenty enough for a single diaphragm like the 73Dart one that is on my car.The thing is to make sure the check valve is working.I have a slightly bigger cam;276/230@50 and there is absolutely no issue.I was able to get the Dual diaphragm to work with my smaller cam;270/223@50