I just installed a true dual in/out muffler that has a built x pipe and its dumped before the axles. i currently have a 4.8 but a 6.0 is in the way! is this good for my truck?

 

let that thing breathe throw some lt's on it!

 

What muffler is it? The 6.0 is picky about mufflers, and many generate a lot of resonance. From the perspective of sound quality at idle and under load, my favorite di/do was a Magnaflow 22", but from one of peace & quiet at cruising speeds, the Flowmaster BBII 70 was superior.

 

Its a dynomax muffler that has the x built in i think its a 20"

 

You will be fine with that muffler. I have DI/DO 2.5'' Magnaflow with cut outs and the truck is faster with the cut outs closed.