High Reving?

Sounds like you could have a vacuum leak somewhere. Check all of the vacuum lines leading to the upper intake. If it still happens then you could go buy a vacuum tester from your local autoparts store and test your vacuum at the manifold. Or, you could always take the car somewhere to get a vacuum test done on it.

FYI - that stock intake manifold is going to really restrict the air going into your motor, therefore choking your power down. The heads & cam want more air...but that stock intake will not give it to them.
I have an Edelbrock Performer manifold for sale right now in the classified section of this site. Upper & lower manifold plus 1/2" plenum spacer for $300 + shipping.