Just bought an '05 Sierra Z71, 5.3L... I replace the factory muffler w/ the original 40 series Flowmaster with the pipe turned down right in front of the rear axle. It doesn't sound bad, but in my opinion, it's not nearly deep enough, especially at higher a RPM. Any suggestions for getting a deeper sound? Is there a deeper muffler than a flowmaster? I'm curious about the 40 vs. 50 series. I used to have an '89 GMC / 5.7 L with the 50 series that sounded awesome, but had no cats, so I guess that's a whole different game. Any help is very much appreciated. Just looking for a deep, mean rumble, not a funny car.

 

Well the new Flowmaster Super 44 muffler is the deepest, loudest, best flowing muffler you can buy from Flowmaster right now. The 50 is not as loud as the Super 40. You should go to flowmaster's website. I have the 40 Series with duals coming out the right side in front of the back right tire and it is actually quite loud. Would be much louder without the cat but you need the cat. Anyway, good luck with that.

 

the 44s are deeper than the 40s... i've got two buddies that recently got them... one's running turndowns on a 5.2 jeep grand cherokee, and it seriously will rumble the ground... the other is running single in/dual out on a silverado, and it sounds alright, its better than the 40, but not just "holy crap that hurts my ears!"