Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec 3L troubles

DMD vs. Stock, Why not? I've tried both and I honestly don't feel much of a difference with the stock pulley so I went with it. Less mass on that outer ring too. If everything else strikes out, change out your damper to stock to test it. A higher inertia damping ring is more likely to cause an issue than the normal one.

Well check it out so you can eliminate it from your list of possibilities. It is just a shot and you can hope it is the damper before you go hoping it is something else because anything else is likely to be more serious outside of the ignition system.
After the ignition system I'd check with things that are supposed to be balanced, like the clutch and pressure plate assembly too. The clutch can throw a spring and cause a balance issue.
The rpm limit on our cars isn't there for the engines's sake. We already know that this engine car purr along at 7200-7400 without any issues with the stock parts. The clutch assembly and transmission input shaft.....now that's the stuff we don't know. Many times engines are electronically limited to protect the transmission from damage. A recent example is the Mazda RX8 automatic. THey cut off a thousand rpm from the MTX rpm range when using the auto. THat thing redlines at like 9K rpm and the atx is like 7K or 8K rpm. Looses like 30 hp because of it too.
Most people knocking out higher rpms are not running stock hardware but you should ask around.