Hi, I have a slightly modified (Elderbrok intake, hotter cam, Holley carb) '72 455 Buick Riveria GS with dual exhaust. I presently experience a constant drone at highway speeds and want to upgrade the exhaust system. What type mufflers do you recommend so that I maintain performance and the big block rumble at low speeds while quieting things down on the highway? I'd be willing to sacrifice some rumble to get rid of the drone. What size exhaust should I use? Dan
If you don't like the "drone" then stay away from Flowmaster mufflers. They tend to have a "resonance" at certain R.P.M.'s.
I would also like to know about those Aero Chambers. I am also curios about the Moroso Spiral Flow(?) mufflers. Anyone,.....anyone
Walker Super Turbos or Hemi Turbos on a 2.5 inch system are really a good choice. These are also branded as Dynomax. They are loud only when you want them to be :Brow: and I'm sure you know what I mean by this. :Brow: At idle they have just a low rumble almost like a "stock" muffler. At freeway cruise you can tell they are back there but its mellow. To really remove the drone on a dual system with performance mufflers you need a crossover pipe to balance the exhaust pulses between pipes.
Dynomax by Walker has the least noise and the best flow in any head to head test I have seen . (Not all have been tested ) In general the longer the muffler the better the flow which is just the opposite of what many people think would be the case.
According to Hooker flow data, Aero Chambers flow 440 cfm while the MaximumFlows did 595 cfm. A straight pipe did 600 cfm. Some GN guys seem to like the Aeros.
