Yes they were, it was pretty rich from the factory, the Preditor leaned it out some, but it sould be leaned out more, but the Preditor has it's limited, for the best get a dyno tune, if your truck is all wheel drive it's harder to find a 4 wheel dyno but worth looking for.hvcone, were your original pipes black at the output? I have what I believe is significant sooting of the pipes. I am reluctant to get a tune done until I get the headers bought and installed. The Borla instructions recommend cutting the pipe after the muffler rear mounting brackets just before the rear spring, I may do that but I have to remove the springs anyway to put the GF 2/2.75 lowering kit on so am up in the air about the process.
The 05' muffler would be nothing like the 07', the 6.2 uses a larger front and rear pipe dia., you would be better off asking a member from the 02-06' Forum. It's not uncommon for GM to change the muffler part number several times for different manufacturers that supply the muffler or if there has been any slight changesAlright thanks. I looked at the muffler on my 05 and it had a bunch of different numbers. Guess they've changed them as well as made them sound better.