The 817460 Flowmaster American Thunder Classic Axle Back Exhaust System for the 2005-2010 Ford Mustang GT & GT500. It features a pair of specially-designed 40-series mufflers, which provide a deep and aggressive exterior tone. Through extensive testing this kit has shown horsepower and torque gains, as well as a weight savings over the stock mufflers. Features 4" polished stainless tips with the Flowmaster embossed logo.
This aggressive sounding system is designed to replace the original rear mounted mufflers located behind the Mustang rear axle. With easy fit in mind, the exhaust system is mandrel bent from 16 gauge stainless for maximum performance and includes specially selected 40-series mufflers to support the performance image of the car.
As an American Thunder Mustang Exhaust System, it delivers an aggressive exterior tone with moderate interior sound level that is suited to the Mustang enthusiast who wants their performance to be heard. Like all Flowmaster Exhaust Systems, the benefits include improved throttle response, power and mileage. Designed for an easy fit, the system does not require cutting of the factory system and includes all necessary parts and hardware for easy installation.
I purchased these Flowmaster 40's to get the maximum sound for our completely stock 08 GT automatic. Flowmaster advertises these mufflers as aggressive and with significant interior sound. They are correct about both! They create serious droan in the car from 1600-2000 rpm. Dont get me wrong I love the sound and would buy them again , I just want to make it known the drown issue. I purchased a 5×8 roll of 3/4" sound deadening to line the trunk which helped a lot. The install went great for left muffler but the right required some tweaking to get the perfect fit. Altogether I am happy with the purchase and it now sounds like it should at start up and when you mat the gas peddle.
Flowmaster - The Exhaust Technology Company Flowmaster operates the only exhaust Research & Design facilities of its kind in the world, centered around the SuperFlow SF-7100 engine dynamometer complete with E.C.A. (engine cycle analysis) equipment and also SuperFlow chassis dyno's.
Through use of these dyno's, Flowmaster's engineering staff can track the complete engine cycle in millionths of a second and can obtain exact technical data of each degree of cam rotation, from induction to the tip of the exhaust system, while also showing the power numbers that really matter, the power numbers "to the ground."
Flowmaster also utilizes Spectrum Analyzers to fine "tune" the sound of each of the eleven different series of mufflers that Flowmaster currently offers, both for peak performance and just the right sound levels and tones. Flowmaster's dedication to quality is what makes them the exhaust industry leader for Latemodel Mustangs and SVT Lightnings!