Shadz

I have a '75, current Dynomax mufflers have too much drone. Any suggestions? Not looking for extreme but do not want the silence of a vaccuum cleaner. Thanks

Would short tube headers with just normal mufflers give a nice mellow sound?

MelWff

Dynomax makes different mufflers. Choose one that better meets your noise requirements or look at the Dynomax VT muffler which cures drone issues.

69427

An H pipe up front, near the header collectors or near the bellhousing, does wonders for reducing/eliminating drone. Worked great with my engine and Dynomax mufflers..

erufle

i think the stock manifolds are as good as short tube. If you are going to replace the stock manifolds you have to shell out the big money. From what I’ve heard that will get you, at most, 30 hp if you also get high-flow cats, 3” diameter tubes, cross-over, and mufflers that are so small/thin that you have to have perfect vision to see. Some people say they empty the contents of the cats but you might as well get an Off Road system. I have seen data suggesting the primary header tubes be 1 7/8” diameter. They have come out with 2” primaries but you would have to keep your rpms pretty high. Size isn’t everything. The speed of your exhaust slows down as the diameter of the tubes gets larger. When that happens exhaust particles kind of slow down creating a swirling motion. That means some of the particles, not all, actually go backwards and that means the pressure acting against the exhaust trying to escape the combustion chamber. A 350 seems to do well with 1 3/4” primaries, but all that I’ve just said goes out the window if you race a lot and your RPMs stay high. Then, the exhaust system needs to be wide and with no obstacles like a catalytic converter.