In my experience, a "high-performance" aftermarket cam is generally going to give you around 14. A stock cam is going to give you 17 to 20.
That is basically necessary to operate accessories like power brakes and air conditioning.
The Pantera power brake booster will work down to about 14 or 15 inches at idle. You will notice the pedal getting a little harder even at that. At 12, you have lost your brake assist and the simplest solution is to go to a vacuum pump.
In my opinion a cam generating only 7 inches at idle is a full race cam and doesn't belong on a street car. There are other issues with it besides just low idle.
It has too much timing overlap. I'm not going to debate how it got to that combination. That is for a cam designer to explain.