My 440 Challenger has Hooker headers, but the rest of the exhaust is ill-fitting, rubs against the frame, the chrome extensions stick out too far, etc.
Can someone recommend a good y-pipe or x-pipe exhaust with real quiet mufflers and stock exhaust tips. It's a street car so I don't want a huge 3" system that ruins bottom end torque.
Actually, I wouldn't mind keeping my mufflers (Flowmaster I believe).

In my experience, Flowmaster and quiet are an oxymoron! While it is rather expensive, I can heartily recommend the TTI 2-1/2 " X pipe system with the Dynomax reverse flow mufflers that come standard. The X pipe changes the pitch of the exhaust to a lower key sound and the car will really sound nice while letting you enjoy your stereo . I am in the minority around here, I like flying under the radar !

I've heard good regarding accurateltd. just me I dont think going to 3" over 2.5" will reduce torque but in fact will gain some as any restriction past the collector hurts you, tho the big problem with a 3" system is noise control & I think added glasspacks alongside the rear leafs along with your choice of muffs up front would be mandatory for a 3" system & mandrel bends with any system. I've heard flowmasters can be raucous. tuned lengths/proper dia is primary tube territory. I think the absolute best is cable or vacuum (better yet) cutouts at the collector. Power (& noise) only when you need it & quiet the rest of the time (you will get along great with cops/neighbors) then when needed open it up & 10 seconds later the money will be in yours'(or a third parties') hands & they'll never know what hit em!

TTi 2.5"

Same here, great fit

I am going with the TTI 2.5" w/X pipe but using Dynomax Ultraflow muffs instead of the Super Turbos that come with the kit, but I'll also be using exhaust manifolds instead of headers on my 440-6...x pipe supposed to be a little more quiet than h pipe, ultraflows will flow a little more than the turbos...fwiw, I loved how my cuda sounded with the Hooker Super Comp headers straight through to the 3 chamber Flowmasters I had on for years...

If you're upgrading to a 2.5" system, such as the TTI that some people are suggesting, be aware that OEM tips won't fit. TTI offers some very nice replacement tips for both their 2.5" and 3.0" systems.

If you want "relatively" quiet, don't use the Dynomax Ultraflow mufflers. They're a straight-through design and are significantly louder than the standard Dynomax muffler that TTI offers (just can't remember that model's name at the moment).

Also, having a 3" vs. a 2.5" system has nothing to do w/ the engine losing torque. A bigger system simply breathes better and has less restriction... and is a bit louder.

FWIW, I have TTI 2" headers, their 3.0" X-pipe system w/ Dynomax Ultraflows, and their replacement tips. Cheap? NO. But their stuff is high quality and usually fits w/o TOO much hassle (but not necessarily NONE).

My 71 V code Challenger has a TTI exhaust on it, it's quiet and high quality. No complaints.

The operative word the OP used was "real Quiet". The x pipe and super turbos will achieve this without sounding like Mom's Buick. In reality, many of the cars I see running 3" are not making enough horsepower to really need it and there is a very noticeable Db increase in 3" over 2.5. I will say, I just put a 3" TTI on a friends 493(586hp) RR, using the x-pipe and the Super Turbos and it was very low key! Not as quiet as my Hemi with 2.5 TTI, but way better than I expected. I am a big fan of the X-pipe and theway it tones down the noise.

I would check out both TTI and Accurate for what they offer for fitting to your Hooker headers and your mufflers (if you are keeping them). Your request is just a bit different than what either typically make, which are systems to fit their headers and mufflers or stock. You will need to get some dimensions. The length of the muffler, the in/out offset if any and the width and height. Also look at what type of hangers each offers vs. stock. The position of your collector flanges will be the harderst to measure, and will only be a good fit if TTI or Accurate has used the exact same headers for a mock up. This portion you may want to have a semi-local shop make up or fit. Go to a car event where there are street rods and ask where the ones with nice workmanship were done.

Sizing. Going to a larger tube will slow velocity and let atmospheric pressure move up from the tailpipe at low rpm. For street use, keeping velocity up at less than 3000 rpm is more important than what happens at 5000 rpm. However a good balance is achievable.

The exhaust gas takes up less volume as it cools. Just because a 3" collector diameter is the right size for high rpm performance, doesn't mean the whole system needs to be 3".

For a street car with some interest in occassional 1/4 mile performance, consider whatever is attached to the collector as an extension of the collector. Wherever the size drops, or there is an interuption with an H or X, that's the effective collector length. You can change the sound reduction and help or hurt power in certain rpm ranges by where the H, X or drop in size is placed.

You can use Pipemax software to estimate best placement. It will be most accurate when adjusted with specific dyno data. But I can tell you that for a close to stock engine Pipemax says the collector should end around 20" from the end of the primary pipes. Next best would be around 40" and third best around 80".

My experience and observations with A-bodies has been that TTI systems use stock tail hangers but not the muffler hangers. Whereas Accurate uses the stock style muffler hangers but nut not always the stock style tail hangers.

(If you want "relatively" quiet, don't use the Dynomax Ultraflow mufflers. They're a straight-through design and are significantly louder than the standard Dynomax muffler that TTI offers (just can't remember that model's name at the moment).)
Are the ultraflows really that much louder than the SuperTurbos? Someone posted a chart a few years ago with specs on aftermarket mufflers, I don't have it handy at the moment, but it listed the db's and they weren't much more, and the X pipe will tone it down I'm hoping. Does anybody have any experiences with both? Thanks to the op on the post

2.5" exhaust will maintain flow velocity & will perform better in low-end & midrange, plus with the right mufflers, will perform just fine in the high RPM's as well. If you want to use Ultra Flos, use them in conjunction with some 16"-18" resonators in the rear.

On the TTI note, I have a buddy with a 70 Challenger 440-6 & the whole system headers back. One of the primaries makes constant contact with the torsion bar & the only way to remedy it is to dent the primary. Also, he got the 3" system with Super Turbos & it sounded great at first, but once the packing blew-out of them, they got SUPER loud. My chambered exhaust on his car even in 3" would be quieter than the Super Turbos now. Plenty of room for resonators in the tail pipes on an E-Body.

What is your performance level?

We'll have to agree to disagree. Back pressure is bad and, even factoring in the tuning effect of the exhaust as a collector extension, 2.5" is too small, since 3" or 3.5" would be the size of the collector of the OP's headers.


I've been giving that some thought on my Challenger, too. I like the better performance of the Ultraflows, but wouldn't mind toning down the sound level a bit.

I changed the exhaust on my Challenger from Hooker Super Comps, 3" TTI H pipe system with Dynomax Super Turbos to stock exhaust manifolds, 2-1/2" TTI X pipe system with Dynomax Ultraflows. Neither system had resonators in the tailpipes. Actually, I believe the factory round mufflers were on the tailpipes after the axle and the resonators were just ahead of the axle under the rear seat area where my mufflers currently reside. It's hard to say which one is louder since I never tested it with a meter, but it's definitely a different sound. My situation is not a very good comparison between mufflers since there were other changes also. That said, the older exhaust had a mellower sound but had a noticeable drone at highway speed. The drone went away but the Ultraflows are quite loud being a straight through design. I've also thought about putting resonators out back to quiet it down a bit.

Mine has the TTI 2 1/2". Very quiet. Car runs 12.50s through the full exhaust. Only issue fitting was the reverse rod for the 4 speed needed modification. As far as the stock tips, they are easy to modify. Cut off the small inlets. Oval a piece of 2 1/2" tube very slightly and weld it on. Mine has been this way for 15 years. The exhaust system still looks and functions like new. Although the TTI headers themselves are in need of a recoat this winter.
Doug

Related to this topic since chrome tips are part of the complete exhaust system and contribute to the overall sound / noise level

What company makes the most correct reproduction Challenger chrome exhaust tips ?

Thanks guys for all the comments. My 440 is basically stock. Buy the TT1 2.5" system straight from TTI?
thnx, J

Call and check with Accurate in Oregon.. Good people who I am sure would help you put together a system..

Big black Friday sale going on there right now also..

Their system on my 67 B body has worked flawlessly for 10 years.

Call around to some of the vendors, TTI is draconian about discounting their product, they will drop a vendor immediately if they find them discounting, but as one vendor told me, "they can't stop me from giving you free shipping". Ask for it, if they won't do it, call someone else, I recommend Mancini.
One of the other posters mentioned about another muffler only being a few decibles louder... Db is not linear, 3 or 4 Db is a very big difference! Also, just tell them which Hooker headers you have, the only difference in their systems is the short transition piece that goes from the collector to just past the crossmember cutout.