headers and straight pipes

[bojak]

Originally Posted by cleansquare

I have long headers on a stock 350 with 2.5" true duals into flowmaster super 44's with an h pioe right before the mufflers and it is a good rumble. Not loud at all but you can tell it sounds good. Also flowmaster 40's are.nice
Posted via Mobile Device

Ok can someone help educate me on the difference between the series of flowmaster mufflers? What is the difference between 40 series and others? Is it flow or all just sound? Like picking a guitar chord? I know slightly more than nothing about these things but i try not to let that stand in my way.