[patrickt]

That was a successful test. I know in our local club we have a set of shorties that we test with and scare neighbors with (they are not really side pipes at all more like two foot long side pipes). If your side pipes were extra restrictive, and since your engine is really just a big air pump, that could account for the reduced venturi air flow that you are seeing and the corresponding lack of power and inability to open the secondaries. So, I agree it's either the carb (which could still be just malfunctioning despite the fact that we got the secondaries to open with the rag test) or it's restrictive pipes. I think it's going to be one or the other so I would first try swapping out whichever part was the easiest for you to swap out. If the dyno guy could pop on some temporary straight pipes out of the primaries that would be lovely. If not, swapping on a mechanical secondary carb would be the next test. Let me ask you, is your Cobra loud enough? I know that's a subjective question but does it ever set off car alarms when you go by them parked on the street?