I called flowmaster about this exact same issue. They said that the only acceptable muffler for the hemi is the 70 series. Evidently they tuned it specificall for the 3rd gen ram. It is loud when i want it to be with my hemi.

 

I just spoke with a rep at flowmaster and he said the 50 series was designed specifically for the hemi. Are you sure about the 70 series on the hemi? The rep said the 70 would decrease the horsepower. The reason I ask is that I want to change out my 40 with something a little less painful on the neighbors.

 

Was that 50 series for the catback system or true duals?

 

The 40 I just had put on was a catback. I am not sure about your question on if the flowmaster rep was referring to 50s related to a catback or true duals. The rep mentioned the dual outlet, so wouldn't that mean the catback?

 

Yea, you're probably right about the 50 being a catback. I'm in contact with a group in Dayton, OH that will hopefully be able to duplicate the catback system that I wanted from flowmaster but in a stainless setup. I want this stuff to last. I still plan on using the flowmaster 50 series though and a dual outlet.

 

Do u stilll have your 40? and don't use it?

 

From what I've read here, I must have the 40. I bought my ram used and it already had a flowmaster single in dual out...and at 2k RPM the drone makes my eyes shake...it sounds really good at idle and at 1/2 to WOT, but at 2k...ouch

 

I spoke to a flowmaster rep again today and this guy told me there is a special 50 series muffler made for the Hemi (50 series HD). He said this is close to the 50 series SUV model. As far as the 70 series, the guy today told me there would be no loss in hp but the hp gains would not be as good compared to the 50 series HD. I'm replacing the 40 I had installed last week with a 70 this Saturday. Luckily, the place that installed the 40 for me is only going to charge me the labor to change it out and not for an entirely new muffler. My neighbors are already thanking me.

 

I have 40's on my hemi and I wish it was louder. I like rolling down the back windows to hear it more. Sorry but F the neighbors, I was here first. hahaa

 

if you get a catback system from flowmaster its gonna have a 50 series.

another thing to know about the 50 series is theyre all pretty much the same.check the dimensions of the mufflers.the 50 delta flow and 50 series are the same.the 50 suv is about 1 inch longer to keep the noise down.

a 40 is loud and is made for camaros,5.0 mustangs and cars like that.it will work on the truck but the hp gains wont be felt until you reach 85+ mphs.