No top end power, need help

UPDATE:

I tried tweaking with it and still am having trouble. I noticed that by having the timming up around 15* I seem to be getting a little better upper end power. What Im trying to get a handle on now is the idle. It is rough (still drivable) and at stop lights I pop it into neutral but still runs rough, especially after it has come up to temp.
I borrowed a cheap SunPro Tach II and hookaed it up and my idle is at 3k. I tried all sorts of things (timming and idle mixture) to get it down, but it really does not want to drop below 3000 (according to the tach). The carb is a used edelbrock 1406 0693 and I checked the secondaries and they seem fine. At full throttle they are open all of the way.

At 3k RPM there was no noticeable suction coming out of the left side vacuum port of the carb. But at a higher RPM the vacuum does kick in and is fed to the distributor.

And like I said earlier my MPG is bad, in the low teens. Any ideas/what next