I have a 67 Camaro and it has a 350 in it. Well I installed Edelbrock cam #7102 which specs as follows: 234/244 @.050" .488/.510 @valve and 112* lobe seperation. My problem is that at idle or when backing up I only have one or two, if I'm lucky, power brake applications before it loses vacuum. If the engine is at any RPM other than idle it's fine. it's only when I'm idling or backing up. I'm sure it has to do with the cam, but is there anything I can do to help it? I have replaced the check valve on the booster, but nothing. Any help would be greatly appreciated.