I am having a hard time getting it to idle. I can get it down to 1100 rpm then the vacuum fall to 8 to 5 in drive,then the power brakes are hard as a rock. Even when the vacuum is 12 the brakes are hard. Need about 15 for the brakes to fill good. Is this a vacuum (cam) problem or a booster problem? I am running a stock 904 if it was a 4 speed it would be better I have 10 to 12 vacuum in park. If this is how this cam is how can I get my brakes back.