3inch header to 2.25 exhaust to 2.5 inch muffler?

[Voetom]

Hi All,

I have a 68 charger with 383. The car was restored about 10 years ago, but im not sure whats inside the engine (likely stokish cam / 650 carb). I've had doug's 3 inch headers installed a while back, the rest of the exhaust is 2.25 inches (stock) with an h-pipe. I also and electrical cutouts in the first part of the exhaust before the h-pipe. I sort of love/hate my cut outs, at idle they sound dope, at full throttle they sound insane with awesome pops on decell, but in the middle - just driving with them open, they sound like a busted muffler. With cut outs closed, the car is very quiet, like too quiet for my taste to be honest (in the past I had a 73 charger with a mildly built 440 and supertrapp exhaust, that sounded dope, but i don't want it that loud tbh).

On my recent shop visit, i noticed that my mufflers have started to rust out and developed some holes, so its time to replace them. I think i like the magnaflow exhaust, so I have two options.
1. on their website I see an option to buy a headerback 2.5inch exhaust for about $1,000k (would need to be welded/installed, so another $500-600 or so), then I'd probably want to install the cutouts again, so that would add another $500 for the kit and welding.
2. I also see that I can buy just the mufflers, but those are 2.5inch (vs 2.25 that I have on there now), but it would only cost me a total of about $500 to install (about $250 for welding, and $250 for just the mufflers).

So naturally, ideally, I should do option 1, but it would be about $2k. - would i get more hp/tq that I would feel out of this set up? Would sound be noticably better with this option? more importantly, if i do upgrade to 2.5 inch cut outs, would they sound better and should i install them after h-pipe/xpipe for a better sound (currently, they are installed after header before hpipe)?

With option 2, would it problematic that I have 3inch header, then 2.25 exhaust, then 2.5 inch muffler, then back to 2.25 pipes? would that like mess up exhaust flow/back pressure issues etc? Would the car sound much better than it does now, or I won't notice?
View attachment 1707092
The car is a miami street cruiser, to be taken out with the spousal unit (as required on occasion). So i don't want it super loud all the time (cut outs for that), but would like it better sounding than currently is.

In this vid you can hear the exhaust, at 3min mark I open the cut outs

Dynomax 17748. 20" long body. 2.5" in and out, offset in and center out. Bolt right on. Work great. Perfect muffler when mounted correctly.

 

[dodge73dart]

Hi All,

I have a 68 charger with 383. The car was restored about 10 years ago, but im not sure whats inside the engine (likely stokish cam / 650 carb). I've had doug's 3 inch headers installed a while back, the rest of the exhaust is 2.25 inches (stock) with an h-pipe. I also and electrical cutouts in the first part of the exhaust before the h-pipe. I sort of love/hate my cut outs, at idle they sound dope, at full throttle they sound insane with awesome pops on decell, but in the middle - just driving with them open, they sound like a busted muffler. With cut outs closed, the car is very quiet, like too quiet for my taste to be honest (in the past I had a 73 charger with a mildly built 440 and supertrapp exhaust, that sounded dope, but i don't want it that loud tbh).

On my recent shop visit, i noticed that my mufflers have started to rust out and developed some holes, so its time to replace them. I think i like the magnaflow exhaust, so I have two options.
1. on their website I see an option to buy a headerback 2.5inch exhaust for about $1,000k (would need to be welded/installed, so another $500-600 or so), then I'd probably want to install the cutouts again, so that would add another $500 for the kit and welding.
2. I also see that I can buy just the mufflers, but those are 2.5inch (vs 2.25 that I have on there now), but it would only cost me a total of about $500 to install (about $250 for welding, and $250 for just the mufflers).

So naturally, ideally, I should do option 1, but it would be about $2k. - would i get more hp/tq that I would feel out of this set up? Would sound be noticably better with this option? more importantly, if i do upgrade to 2.5 inch cut outs, would they sound better and should i install them after h-pipe/xpipe for a better sound (currently, they are installed after header before hpipe)?

With option 2, would it problematic that I have 3inch header, then 2.25 exhaust, then 2.5 inch muffler, then back to 2.25 pipes? would that like mess up exhaust flow/back pressure issues etc? Would the car sound much better than it does now, or I won't notice?
View attachment 1707092
The car is a miami street cruiser, to be taken out with the spousal unit (as required on occasion). So i don't want it super loud all the time (cut outs for that), but would like it better sounding than currently is.

In this vid you can hear the exhaust, at 3min mark I open the cut outs

If your replacing the entire system go with the larger pipes to match your headers and a crossover. Flow is important, you don’t need any back pressure.
As for mufflers I highly recommend the Flowmonster mufflers which are made by the same company as Flowmaster
They do have other sizes.
Here is a pic of the part number etc for the 3”.
You’ll love the low throaty idle and rumble when reving it and still have a nice quiet enough ride to carry on a normal conversation.
Oh, and you can’t beat the price. I got mine on Amazon.
Let me know how it goes.

 

[zyzzyx]

I can't tell you how it sounds because mine is not running yet but I went with the Holley/Hooker Blackheart
system. It's all 304 Stainless and would be perfect for your app. I added two Stainless reasonators in the back
and it will last forever. It comes in 2.5" and 3". I went with the 2.5 as per the Mopar engine manual rec's. Got it at Jegs.
Check out the pic's.

 

[troublemaker]

After a ton of research I've purchased 2.5" Dynomax Ultraflo Stainless Steel mufflers for my 70 Roadrunner. I bought the longer ones that will fit perfectly with TTI's header back H pipe system (Dynomax Part number: 17289, I believe). Right now Amazon has the best price by far on these right now which is why I went ahead and purchased them even though I'm a year or so out from doing the exhaust. Look up TTI they have a great reputation and are less than what you're quoting.

TorRed, I would be interested in how your TTI EXHAUST fit. I also have a 70 Runner, with Hedman long tube headers. Trying to decide if I should just weld up a system or buy the TTi setup. Did you buy TTI headers? Are you using the H pipe setup. My biggest problem is fitting the left header around the frame and other components.

 

[j-c-c-62]

They're not. If I'm going to replace the exhaust, it definitely ain't gonna be 2.25". 2.5" sounds like the way to go for a mild big block street car.

A 2.5" pipe vs a 2.25" has over 20% more cross-sectional area, that 1/4" is effectively a lot.
I personally am going with 3" to an electric cut out and then step down to 2.5" mufflers on a 500"+ RB

 

[j-c-c-62]

Check out the pic's.View attachment 1802614View attachment 1802615View attachment 1802616

In that 2nd pic above, what is that thick black ring? on the DS just behind the front u joint? Is that the DS safety hoop?

 

[33 IMP]

In that 2nd pic above, what is that thick black ring? on the DS just behind the front u joint? Is that the DS safety hoop?

Driveshaft vibration damper.