[JB34]

I had the same problem when I changed the cam. One of the local tracks imposes noise restrictions and I solved the problem with a purchase from Summit. Vortex cones, as Rick Lake suggested. They aren't cheap, but worked on my small block. (I have a Factory Five with mufflers.) They are supposed to drop the level by 3-4 db and if that isn't enough, it would be easy to add some temporary steel wool to pass the test. Note: if you plan to take them out (as I do), bend the three tabs inward or you will have a tough time getting them out. They recommend welding them in, but do come with nuts and bolts to secure them. I use one only screwed in from the back. Worked for me.