I just bought myself a '05 quad cab w/the Hemi. I talked to a guy that owns his own muffler shop and he said that he found out not to long ago that you could not put a regular 40 or 50 series muffler on a Hemi because it will mess up the timing of the engine. I have never heard of that. I didnt ask him to go into details but I guess it has to do with backpressure.
I was wanting to get the Super 40s. Has anyone ever heard of this?

 

I've never heard of it "messing up the timing." Now, I have heard of the Hemi's being picky with backpressure. That might be what he meant.

I have an 04 Hemi with 40 Series Flowmaster. I found the diameter of the pipe played a larger role than the muffler itself. Too large a pipe and you can lose some low end grunt. Bigger is not always better when it comes to exhaust. Personally, I'd go with 2 1/4" or 2 1/2". I ran 3" and noticed the loss in low end. But when I switched to a smaller pipe, it came back.

The size of the pipe will also play a role in sound. My larger pipe was louder up to 3,000 rpm's but got raspy over 4,000. The smaller pipe is deeper, and keeps that sound throughout the power band.

 

I have a super 40 and I have had no problems with losing back pressure. Just make sure if you are running duals you have 3" in and dual 2.5" out, it will keep the balance. If not than you can have a single 3" in and out. I am trying to get a sound clip up.

 

I've had my 40 series on for about 2000 miles now and have had no problems.. Runs like a champ!

 

I appreciate the replys. Yeah, he put exhaust systems on both my brother's truck and my dad's truck. He has been doing it for a while but I need to talk to him more about it to see why. Thanks

 

Just to let yall know that I called flowmaster and they said that the 50 series HD is recommended for the Hemi engine b/c it allows more flow. He said that a super 40 doesnt allow as much flow but it can drop the horsepower a little.