Cobra owners of a flutter, flock together - or something like that.........
Undy, you ran the 3" inserts over the louvers? No wonder the exhaust was so LOUD!!! This may also have something to do with the "flutter" you guys are talking about, as Undy said he did not have any with the mufflers going with the grain. I recommend going into the louvers (against the grain) for max noise attenuation, but they will flow either way of course. From what I've heard from several customers, they are about 3-4 dBA's louder going over the louvers (or with the grain). There will be a little less drag, but I don't think there is a big trade-off.
Here's a video of Cobrapacks on a Viper....................I know you are Ford guys. Wait til the end, your Ford interest will be greatly redeemed, trust me!
Grab a coffee, beer, or Dr. Pepper - this is about 10 minutes of some VERY neat exhaust analysis. It's also a lesson on how to make a V-10 sound GOOD! Which mufflers sound best??? Enjoy:
http://www.pod9.com/ant/viper/exhaus...k_dyno_day.wmv
-Eric