I am currently running true duals, flowmaster 40 series 2.25" O/C  (model # 42441) under my truck.  I have heard a lot of good things about the 40 series mufflers such as good tone and loudness and this is why have decided to go with them.  However, mine just do not seem to be as loud as other 40 series i have heard.  I was thinking maybe my catalytic converters could be replaced with high flow cats to achieve my desired results.  What do you suggest?  Will high flow cats achieve a louder sound or do i need to go with another rig?  

CAT's do effect sound some but hiflows are not going to change this much and are basically a waste of money. BTW, you are going to see a loss of response, efficiency and MPG at lower RPM's with true duals because contrary to popular belief, your engines needs some back pressure to do its best in lower and middle RPM ranges so that sound is going to cost you more than you think. You will not find duals on any of my 4x4's (I have 3 of them too)  

Thanx for the post man.  what do u think i should do if the cats are a "waste of money"? headers? or should i switch to glass packs?  i just dont want the 5.3L V8 so sound cheap.  

greyfox919:
Thanx for the post man.  what do u think i should do if the cats are a "waste of money"? headers? or should i switch to glass packs?  i just dont want the 5.3L V8 so sound cheap.

Look, I am not trying to sound ultra conservative here but it is just that things are not as they seem with exhaust systems. Many seem to think that answer is to get exhaust out of cylinder fast but this is a misunderstanding, especailly at lower RPM's. Modern engines are tuned to expect a bit of back pressure so that exhaust escapes slower and more of energy from the expanding gases is coupled to crankshaft. Then as RPM increases the tuned intake makes up for the little extra back pressure and the result is a broader power band. When back pressure is removed, lower and mid RPM power takes a dump for a few extra HP at upper RPM's. The net result is less usable power and reduced MPG in city/urban setting. Glass packs are the last thing you need because they have no back pressure to speak of. If you want a dipper sound and must have duals, try this, run two 2 inch down pipes to mufflers and install a cross over pipe between them (it balances pressure and improves sound) and then use a 2.5 inch pipe after mufflers as this will give a deeper sound. By keeping back pressure higher until muffler, you keep gasses hotter and they expand more afterwards and give a deeper sound. This will retain some bottom end and give you sound you want. Even a nice big single in dual out 40 series would work well too.  

thanx man. ur information is handy