Aftermarket throttle bodies tend to whistle. The only ones that don't are the Accufab and Ford FMS TB's.
No info about your car's model year. No info about your car's model year, no mods listed. Make it hard to troubleshoot when we don't know what you have.
That's why it is a good idea to use the sig under the user control panel (User CP) option. It allows you to post your car year & mods, which help greatly when troubleshooting things. No, it is not there for us to snoop and see any "Secrets" you have hidden away under the hood. Be a good stangnetter and update you sig for future reference & don't keep us guessing.