I will be putting it on a 97 chevy truck with a 454 big block, also will this help fuel mileage, and what about preformace air intake will that also help mileage?
it won't make you fail, as long as you don't remove the catalytic converter or O2 sensors. smog laws don't tell you you can't modify the exhaust system downstream of the catalyst. these mufflers usually do give you a small gain in fuel mileage, however if you keep punching the gas pedal to hear the sound you won't see any gain. face it, 454's eat a lot of gas
