Secret of quiet dual exhaust?

The walker catalogue is a good reference for what stock exhaust systems looked like. I could get the link to the correct page to copy correctly but if you go here:
http://www.walkerexhaust.com/catalog/vehicletypescrnexhaust.asp

you'd be able to navagate your self to various '69 Galaxie/LTD systems

 

Yeah that's the same catalog I looked in at NAPA. All it has is the single exhaust system. Funny, because my Dad is an old Napa parts counter guy, and he says Walker catalogs were the same way even in the 70's. They always had to order from one of the other books when a customer wanted duals.

 

One of the options was "w/7.0L Eng. Dual Exhaust". I'll try to upload it.

 

A crossover pipe will actually quiet down a loud exhaust by making the exhaust pulses increase to an amount of around 32000 pulses a second. This is quieter than each side making 16000 pulses a second. Make sure it is a cross over and not an "X" type pipe. They don't work for quieting the pulses.

 

Having had both H and X crossovers behind 351Ms, the X does quiet the exhaust some, but not as much as the H. However, the difference is not all that great. It is sort of difficult to do a direct comparison with my 2 T-Birds, since the H was connected to Dynaflows, and the X is connected to FlowMaster DeltaFlows. Thing is the DeltaFlows with the X are still quite acceptable for noise levels. Completely possible to talk at normal levels in the car, and they don't wake up the world. That is with Hooker long tube ceramic coated headers as well.

 

Just drove through the Burger King drive-thru, wow is it too loud. Glad to hear that the H-pipe should even out the pulses, because it really sounds like a truck! Hopefully be taking it to the muffler shop SOoN.

 

I'm a little late to the discussion, but I remember reading an article years ago about the best flowing stock mufflers and the winner was from a 70's Chrysler Imperial and weighed in around 22lbs.! And if memory serves me, it was also the quietest of the mufflers as well.

A quick google search turned up a couple of articles confirming what I stated above:

http://www.draglist.com/stories/SOD Mar 2001/SOD-030101.htm

"[FONT=Arial, Arial, Helvetica]Another consideration is in the "behind the collectors" area. The "old" Chrysler Corp. (before the Germans!) did exhaustive research into race exhaust systems in the late 60's and early 70's. What they found was that the addition of an "H" shaped cross-over tube behind the collectors added mid-range torque with the surprising benefit of quieting the overall exhaust noise. It even made the system sound better to the ear. Back then, in the days of glass-pack mufflers, the engineers found the best performance mufflers were Chrysler Imperial mufflers and the Chevy "turbo" mufflers originally used on the turbocharged Corvair Spyder vehicles! (Yep, I DID say "Corvair!")"

Looks like it may have been '71 Imperials with 2-1/2" in/out mufflers (3466644) from what I've found.

For what its worth...
[/FONT]

 

Here is a great article with track performance testing on different set-ups ...

http://www.pontiacstreetperformance.com/psp/exhaust.html