I agree, I've seen it. A buddy of mine has been running the same combo for 7 or so years. Ran high 10's at the beginning, with little tweaks along the way, he ran 10.30's earlier this year. It's crazy. Heck, one of our buddies at the track today has cut almost 5 tenths off his newer challenger times since he first got it, with nothing more than some different drag radials and rims. Most of his gains have just been from seat time and trying different techniques at the launch, etc.

My new combo just may need more tweaking than what I've had to do in the past.

Again, I just don't see 130HP from an air cleaner housing and a header to exhaust manifold swap on a mid 400 hp engine, especially since I've made the header to exhaust manifold switch in the past and only lost around 2 tenths. Who knows though, you can only truly figure this stuff out with testing.

As I mentioned above, I may take it to the chassis dyno for peace of mind, curiosity, and to see if we can find any smoking guns. May have to check some things over the Winter and get back after it next year.