Oh the noise!

I bought a Summit 3" Kit for my 408 and had a local shop tweek the fitment.
Before the shop it was pretty loud but after they were done I was amazed how much quieter it was ! And this is a .648 solid roller Motor .
They Rerouted Some pipes, welded all the joints , added a crossover and got the mufflers back where they should be .

It may not be your mufflers ....