I see there are some people on this board who are very knowledgable about exhaust system sound. Rather than steal the other thread or pile on, I'll start a new one. I have a 61 T-bird conv that is presently running 2in diameter straight pipes, no crossover. (The stock mufflers are removed, tailpipes end 2 feet short of the bumper). OEM was 1 7/8 duals with a crossover, resonators in front of the rear axle, and big round tri-flows in the rear corners. I love the sound at idle just the way it is. You can hear the corn-popper effect of the hot cam. The sound at cruise is not objectionable. The sound under stiff throttle pressure is LOUD and SHARP, ...painful actually. What can I do to still hear the idle but soften the noise on acceleration? (I had a car in the past with duals, no crossover, turbo mufflers, that had a bad drone. I don't want that again)
I'd put in a cross-over (or X-pipe) and install some straight-throughs at the very rear. These cars had a great sound with that set-up, it's what I ran on my early '60s Galaxies way back when.
Like bodacious says, straight-thru muffler designs are the closest thing to what you're wanting. That pretty much means glasspack. If you want an oval muffler body, magnaflows are basically a straight-thru glasspack in an oval body and they're available with crimp-style construction. If you want true straight pipe sound look at Thorley/Jardine. Their mufflers are oval body with a straight thru perforated tube, but no packing. They are welded construction (not trad looking), but are the loudest sonsabitches I've ever owned and totally have the traditional sound. good luck
Check out the muffler kits on our site www.coneeng.com we are an Alliance vendor and offer discounts for members. You can customize for the sound you are looking for. Can also build your own crossovers and x-pipes with 2-1 collectors.
Cross over is going to smooth out the overall tone. Idle should still be OK. The rapping noise you are getting is the shock wave of the sound pulse behind the one exiting the tailpipe running over it. Basically, think of a hose that is letting out a bunch of water and the pressure has a sudden spike. You get that blob of water AND the hose shakes, that's it. I'd go with the straight throughs. Glass packing only attacks high frequency noise so the rumble at idle isn't going to be exited too much. The 'drone' you heard is most likely a standing wave in the pipe that sets off something in the car. Mufflers are all about location, location, location. Hope this helps. Use clamps, you can swap stuff around then!
On my 1962 Thunderbird I ran 2 1/4 from the manifolds all the way to just over the rear axle. Then the final few feet I ran 3 inch. The 3 inch are about 3 feet long. The mufflers are Flowmaster 40 Series and there is no crossover pipe. This set up sounds great.
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