Yesterday I changed my muffler out and went with a 18" si do magnaflow. I was going for something quieter which it is. It is not dumped and ran out the back. Its making this air sounding popping noise kinda like chucka chucka.lol Yes i have a cam but thats not it my other muffler did not do this. Has anyone ever have this problem or any suggestions. I like the sound of it other than that its annoying.

 

ive got a 2006 4.8 with true dual straights and no mufflers, it sounded smooth, then i put in a 206/212 comp cam, and i got kinda the same thing. sounds almost like a clunking in the cab. i guess its just the match up of parts, i ordered a spintech 9000 dual in/out muffler, it should be in here very soon. if that fixes it ill let you know. if so, i guess its just the different combinations. lol best of luck to ya

 

deffinately fixed my problem. so i would just go with another muffler? best of luck!