Suggestions Wanted For 408 Stroker Mufflers

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There's a grey Duster with Borla XR1's. The video is titled , Borla XR1 Mopar 408 idle. Sounds amazing! Hopefully someone can add the link to the video. I don't know how. I have Dynomax Ultra Flows on my 408. Sounds like factory Mopar exhaust to me.
 
Flowmaster mufflers are over rated. Plus the drone noise is awful. Plus there is no reason to run anything more than 2 1/4 on the street but everyone wants bigger is better. 2 1/2 fits ok but not really needed. I'm sure this statement will lite up many :poke: To each their own. But the OP did ask.
 
I know every car is different. I have a 73 Sport with a built 340. I used the Dynamax Super Turbos to replace the Summit Turbos I originally had. The Dynomax sound good at idle, not too loud, and really sing under throttle. But the interior drone is terrible.
 
The OP is putting together a stout stroker combo not a run of the mill pooch mobile wheezing through dinky 2-1/4” pipes. 2-1/4” pipes please.:rolleyes:

Not to mention it will sound like rappy brappy **** hitting the upper rpm’s just like all the other **** sounding cars and trucks running around with dinky pipes.
:rofl:
Minimum 2-1/2” and 3” if you can fit with something like Dynomax Ultaflos.:welcome:
 
In year 1999, I installed a 3" full-length TTI dual exhaust with the long 3-pass Dynomax muffs, on my combo. (the fit was great). They're still on there, and still not rusted thru. And I still like them.
I've Final-drive geared that car from 1.97(double-od) to 5.38s, and it never had any drone with any gear, even with the H removed.
It has a lovely idle, an awesome WOT, and with the current gearing, she cruises at 65=2240 in GVod.It's been that way now since ~2004.
At Part-Throttle and gently motoring, going thru and by 2800rpm, the 367 is just coming up on the 230*cam, and the sound makes me smile every time.
Car goes 93 in the Eighth, without the exhaust, and I'd bet a dollar not much slower thru the cannons.
Never, since that day, have I had the thought, for any reason, to change the exhaust or the muffs; and Never have I been pulled over for loud mufflers.
But yes, that system is heavy. IIRC 72 pounds from the collectors back.
Happy Hot-Roddng
BTW
If yur wondering why I installed the 3inchers, it probably ain't cuz the 360 needs it. But ya know, there's about 3.5 to 4 ft of pipe from the collectors to the muffs.
Now, I'm no engineer, but I got a reasonable idea of how headers work, and a couple of thoughts came to me;
1) the 3inchers have 20% more cross-section than 2.5s, which I imagined should help inertial header tuning and the engine should pick up some torque thru-out the rev range. IDK if it did or not, but I sure can't complain about the torque. and
2) the 3 inchers also have 20% more radiating surface than 2.5s, which I imagined should help the gasses cool and become more dense, leaving more room back at the collector, for the incoming pulses. From stem to stern, that is a good amount of cooling area; and so 93 in the Eighth is pretty good for a small-cam 367
3) I imagined that muffs with 3" in and 3" out would present less of an impediment in the corners of the 3-pass muffs, to the now sort-of pushed-along gasses.
4) My car is a streeter, and WOT-Power is not really a thing, cuz at WOT,
it spins street tires to well past the speed-limit. But low-rpm torque is a thing for me, and it's super nice NOT to have to downshift all the time. And the torque is really great for passing. and
my car is a manual-trans, so no help from a Convertor. She spends most of her life below 3000rpm, so torque really matters.

Your stroker will have plenty of torque down low, so I imagine that none of these points would apply to it. But I can tell you this; as to back-pressure; there is no such thing it ever helping power-production. It may however help in the fuel-economy equation, by stalling scavenging.

and yes the 3inch TTI tailpipes easily snaked over the diff, and between the tank and springs, even after I moved the springs inboard with the offset hangers. No rattles either. Good-job TTI.
 
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I went from flowmaster 40s to Welded Ultraflows. 3" to the mufflers and 2.5" tailpipes. The ultraflows were quieter and .1 faster than the flowmasters. The car still picks up .1 and 1mph with exhaust cutouts. The cutouts made the same difference on my 360 that ran 11.20s as they do now with my 418 that has run 10.40s.

I just recently cut the tailpipes off so I can relocate my rear shocks but I haven't fired it up yet.
 
What ever.... 2.5" is all you will ever need on a street car. Hell even the 426 Hemi came from the factory with 2.5" exhaust pipes.
 
I like using plain old 2-1/2" Turbo mufflers. The kind that every muffler shop sells and the kind that keep the cops and neighbors happy.

Tom
 
Guys make over 800 hp with 2 1/2" exhaust.. Doubt that a 450 hp stocker would benefit for 3"
 
72DartGuy said:
I brought a pair of Flowmaster 40’s to my mechanic and he told me they would be crazy loud. I’d like the motor to purr at idle and growl when ya give it gas, but I don’t want to be that asshole.
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Plus he said this
 
I'm not... but you are still wrong. Don't be hung up about it though. I have had many others tell me I was wrong. They too found out the hard way. Many a checkered flag in this compound. Once you understand what scavenging exhaust pipes do you'll do fine.
 
TF360 said:
You need the right Flowmaster. The Delta Flow 40 series is the right model. They are not too loud, and the sound is unreal. You don't want the standard 40 Series because they are too loud.
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Those are the mufflers I went with. I was able to swap the original ones back for them. 2 1/2” and a straight through design. Thanks!
 
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