Help w/American Thunder 40 Series Exhaust

[IBleedBlue]

I went ahead and put the 50 series delta flows on my Mach and replaced the 40 series. Very satisfied. Cut down greatly on the interior resonance. Didn't feel much difference in performance except that I might have lost a little torque feel. Which is kind of interesting as you would think I would actually gain a little torque. Flowmaster web site bascially says not much difference in flow between the two but lot less noise.