Under the hood noise
 

Hey guys,
I have a weird woosh/flutter metallic noise under acceleration. Ive tried recording it but it cant be heard with the windows up, and with the windows down the air is too loud. When Im next to another car or wall it is very apparent. I have changed all gaskets from OP back. I hooked up my OBD and there does not appear to be a leak of any kind. This noise is driving me bonkers and cant find the issue.
Vortech SC, JDL header, cat back exhaust

Thanks guys

Jack the car up and spray the exhaust with soapy water to make sure it's not an exhaust leak.