Ditto on the quality of Edelbrocks stuff. I am certainly NOT impressed with the quality of any of their products. I'd say ten years back was about the end of their reign of making quality stuff. I too had to fight tooth and nail just to get an RPM cam exchanged because the lobe/lifter wasn't properly hardened/machined and that didn't count all the money out of MY pocket to teardown and clean up all the metal that was left behind after a 20 minute break-in. I just won't deal with new Edelbrock stuff anymore, not worth the headaches.

Anyways- I'm assuming that the needle is fairly steady at 13 inches? What's it do when you throttle it? Or when you hold it at 2000 or in drive under a load?

If nothing else at all, and they are willing to do so, exchange the carb. If it still acts the same with a new carb, obvious the problem may be elsewhere. You do have all the vacuum ports pluged and routed correctly right? How bout that pcv valve?