Looking for some opinions on what muffler would be best for my application. Currently have a 3" downpipe and 3.5" back to the rear axle with a resonator. I'd like to add a muffler in line because at certain rpm's it sounds like a good ole boy truck with and gets that clapping tone. What muffler would you guys recommend that still flows well but will do away with that unwanted sound. Picture of my current setup.

 

If space is an issue, always consider vibrant resonators. They offer this 3.5in version with a 5in round body, it should do more than the little thing you have now.

https://www.ebay.com/itm/Vibrant-179...ry!55374!US!-1

I would have suggested the ultra quiet version but it's for 3in piping, those work super well.

 

I second what FFDP said. Ive always had good luck with Vibrant.
As another option Id recommend the Jones Turbine mufflers. they have an "XL" which has a built in resonator.

 

The muffler may or may not fix it but a helmholtz resonator will work too. Just a little time and math to fix it.