Let's talk about exhaust drone...

The muffler will do it.

 

Cummins were known for being LOUD with straights. I'd put a muffler on that actually works! Lol not one just to get through a DOT inspection. I had a short dynaflow muffler on before and now I have a short resonator. The resonator has a nice tone and the jake noise is a lot quieter but the muffler was much quieter overall. I'll be going back to a short muffler when/if this rusts out.

 

I don't know the model number but it was a dynaflex muffler around 22" long with a taper from the body down to the pipe. The body was around 9" dia. Afaik they still sell them. My muffler shop said ot wouldn't be an issue to get one. It was expensive at 160 bucks but it lasted 9 years so i cant complain.

 

I could be wrong on my price. It was almost 10 years ago. Maybe it was 160 installed. I do live in Ontario. Everybody is rich up here according to the government lol.

 

I would do the muffler. The shorty is a resonator. If it has a baffle in the middle, find a way to push thru it.

 

I'm wondering if the baffle would take care of the drone? My semi and 3/4 diesel both have free flow mufflers. Both have some drone but not as bad as when they were straight piped. It's not unbearable because of where the pipes exit probably directs the worst of it away from me. He's in a daycab. You know, it's not for nothing those baffles are in there... to help reduce the noise....

 

I knew someone who install it. He love it but had a back pressure problem. He punch the baffle out of it and solve that issue. But this was on a 3408.