I am planning on doing a single muffler on my 03 4.8L (I decided not to do true dual because I dont see much more of a hp gain from it on the 4.8L even with a modification like a cam, intake and tune...I mean going from a single 3 inch to two 2.5'' mufflers on a lightly modded 4.8 wont gain me that much hp will it?) Also, when you dump the muffler in front of the axle, do the exhaust fumes seep into the cabin or is it safe to do?

 

from what i have experience it doesnt seep into the cab. it is just noisy.a single outlet will work fine. if i was just going to do a single outlet then i would get them to replace the muffler only since your exhaust pipe is mandrel bent.and put on a good tip.

 

I had a Dump on mine for 2 years never smelled it in the cab....What 02 Denali Said is Right on....It looks good and Saves money....