The new Flowmaster American Thunder system is here for the 99-04 Ford Mustang GT 4.6l,Mach 1, and Bullitt. Owners can choose from the standard aluminized kit or Flowmasters new 409S stainless steel kit.
Official Release
Flowmaster American Thunder system for 1999-2004 Ford Mustang GT 4.6l/Mach I/Bullitt

Looking for that great go-fast sound from your 1999-2004 Ford GT, Mach I or Bullitt Mustang? Now owners of these great muscle cars have the choice of standard aluminized kit construction or Flowmasters new 409S stainless steel kit (PN817312). Both kits deliver that great Flowmaster signature sound, improved throttle response and increased performance.
Available in 409S stainless steel or standard aluminized kit
Great go-fast sound
Improved throttle response
Increased performance
Contact Information
Flowmaster
Web: www.flowmastermufflers.com
Phone: 1-800-544-4761
Official Release
Flowmaster American Thunder system for 1999-2004 Ford Mustang GT 4.6l/Mach I/Bullitt

Looking for that great go-fast sound from your 1999-2004 Ford GT, Mach I or Bullitt Mustang? Now owners of these great muscle cars have the choice of standard aluminized kit construction or Flowmasters new 409S stainless steel kit (PN817312). Both kits deliver that great Flowmaster signature sound, improved throttle response and increased performance.
Available in 409S stainless steel or standard aluminized kit
Great go-fast sound
Improved throttle response
Increased performance
Contact Information
Flowmaster
Web: www.flowmastermufflers.com
Phone: 1-800-544-4761