408 tested with 8 different Flowmasters

Mopar to ya said
I was running 2 1/2 exhaust and Flowmaster 10 series. It was very loud and rapped on decel. I went to 3" all the way with an h pipe and Flowmaster 40 series. Much more mellow and no rapping. I think I want louder, but I believe I am just going to go with cut outs and call it even. Then I get the best of both worlds.
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I initially went with 3" pipe & Flow 40's (with tail pipes) on a 70 El Camino big block (115" wheelbase). Had a drone about 1800-2200 ,went away after that. They like bigger pipes,possibly to flow more across the board. Better mufflers exist.