I have taken that into account and rebuilt the flapper door assembly. The sound comes from a more internal higher location than the flapper door area. Like just behind the glove box area up in the dash. Are there internal parts of the air box that can vibrate?

I agree it seems to be turbulence related.


1968 Pro-Touring Dodge Charger
*2011 Optima Ultimate Street Car Challenge Invitee
http://www.popularhotrodding.com/features/1203phr_1968_dodge_charger/index.html