Well I plan to keep the factory y-pipe and two into one setup when I install the shorty headers. It has a factory type replacement cat, which is supposed to flow fairly well from what I understand, and a factory type muffler. I want a better flowing muffler like a flowmaster or something but have no clue what to get really. I want better performance but I don't want it to be loud or drone in the cab and I definitely don't want a fart can sound! Any suggestions?

 

The factory Y-pipe is the biggest exhaust restriction.

If you can’t get exhaust gasses out, you’re not going to get air in... that’s why the whole performance thing is about matching your components so they compliment each other.

A big gulp tb won’t help if you don’t have intake (ports/valves) to match the flow... valves won’t help with a choked exhaust... a high-flow cat won’t flow any better if the y-pipe is the restriction... all the bits have to be sized to work together.

That’s one of the best problems with doing incremental performance addons... nothing is really any good until you’ve finished doing all.

 

Mufflers don't really make any difference in power output. Dyno tests with different mufflers, (everything else staying the same) were all within 1 horsepower of each other...... So get one with the sound you want.

 

I just don't want to kill the back pressure. As for sound, I guess I'll wait till the headers are on to figure that one out. I just don't want it to be stupid and irritating like some six cylinders I've heard and it doesn't need to be loud.

Edit: I had it out for a while this morning and it seems to run much better at 2000 rpm and above since adding the roller rockers.