Originally Posted By: 440Magnum
The final sound depends SO much on things other than just the muffler that its going to be almost impossible to predict.
I have the straight-thru Magnaflows on my '69 Coronet R/T. It has the factory high-performance cast iron manifolds (not equal-length headers), 2.5" tubing front to back, and an "H" pipe crossover ahead of the mufflers- as nearly a copy of the stock 1969 Dodge system as possible without buying an actual reproduction factory system. Obviously no catcons in 1969.
At idle and cruising, it has a deep-throated burble that sounds a lot like the stock Goerlich mufflers from 1969 did, maybe just a little louder. But as you open the throttle, there comes a point where the sound, for lack of a better description, "punches through" the muffling effect and it almost sounds like straight pipes. For that car (not daily driven) I absolutely freakin' LOVE the results.
Headers would probably change that a lot, since some of the "punch" effect is due to the stacking of exhaust pulses in the manifolds as opposed to equal-length tubes. Catcons would quiet it and possibly make it a little raspier by smoothing the low-frequency pulses through the tubes Removing the H-pipe would likely make it drone at highway speeds. My concern in a car like a Crown Vic would be that even with the catcons, the other effects (and especially if it doesn't have a crossover or H-pipe) would make it drone too much for your taste at highway speeds. But honestly, I've had worse drone on other cars with similar exhaust and chambered mufflers, so I'm not really sure that's necessarily going to be better overall.
Modern muscle car exhaust systems have a whole lot going on *just* to get a little loudness without highway drone- look at the combination of resonators and mufflers on a Challenger, Mustang, or Camaro (not even considering the active exhaust dampers on SRT and Hellcat Challengers, Corvettes, etc.). And the biggest disappointment I see on the forums when people change exhaust systems is that it causes drone.
Thanks.
I'm not doing a system overhaul (it's in great shape, plus that's an expensive endeavor), just a muffler replacement. Retaining the stock piping, all 4 cats, resonators in the tailpipes...