98-02 LS1 SLP “Loudmouth” Catback Exhaust System


Model Number: 31042

SLP?s F-Body cat-backs have always been the best-performing exhaust systems in the business. Now they?re the most versatile, too! Using our industry-exclusive modular design architecture, we?ve developed a line of systems that can be quickly reconfigured to fit changing performance, noise-level, and sound-quality requirements. Simply loosen a few band clamps, swap muffler types, retighten, and you?re done. No other exhaust offers this level of performance and adaptability!

Along with the included race muffler, the F-Body Loud Mouth system is compatible with our original Loud Mouth II bullet-type race muffler (#31067). Get both for complete control over your car?s sound and performance characteristics.

NOTES: Includes Loud Mouth resonator. Loud Mouth II race mufflers sold separately.


– Includes SLP’s infamous Loud Mouth resonator for virtually zero flow restriction and the meanest sound around

– Employs SLP?s exclusive modular technology, making it possible to switch between muffler and resonator types in a matter of minutes

– Engineered and built to OEM standards to ensure proper fit

– Constructed entirely from mandrel-bent stainless steel

– Features a show-quality polished resonator and 3.5″ slash tips with electromarked SLP logo, or 2.5″ “Dual/Dual” tips with electromarked SLP logo. (Choose Below)

– For 1998-2002 LS1 F-Bodies

18 reviews for 98-02 LS1 SLP “Loudmouth” Catback Exhaust System

  1. Rated 5 out of 5
    ( 18 reviews )

    Hunter Clamp (verified owner)

    love it i didnt have enough money to get GMMG for my 02 SS at the time and i wanted it to sound better and i got it the LM1 Kit is easy to install and really good sounding i dont think its too loud like most people say. once u crank it and it gets warmed up the idle sound is almost like stock deeper but not really louder but once u tach it up past 2,500 RPM’s everyone looks. i plan on adding QTP or Kooks LT’s and QTP ORY w/ Cut Outs y-pipe then maybe GMMG. thanks for all the help WS6 Store, had great service and will buy from again.

  2. Rated 5 out of 5
    ( 18 reviews )

    James Thomas (verified owner)

    Have had my car for over a year and finally decided to buy an exhaust. I wanted LOUD. So after listening to hundreds of different camaros with different exhausts i choose the loudmouth. It sounds awsome. Great service and great product. Recomended buy

  3. Rated 5 out of 5
    ( 18 reviews )

    Ryan Perry (verified owner)

    I bought my 98 WS6 with a Flowmaster already installed. I couldn’t stand the drone from them and wanted to go stainless steel. So after about 2 months of listening to cars in person, and listening to the sounds on, i went with this exhaust. It is definitely an awesome sounding exhaust! It has some “popping” in the exhaust because it has such straight airflow, but that makes it sound even meaner. Not very loud at idle, but when you get on it, the car screams and echos for miles. This exhaust makes people turn around and look down the street to see what is coming at them.

  4. Rated 5 out of 5
    ( 18 reviews )

    lydia pina

    Love it..makes me one to drive the car without the radio on..sounds good!!!!

  5. Rated 5 out of 5
    ( 18 reviews )

    Chase Boehmer (verified owner)

    In short, the Loudmouth sounds amazing to me. I was debating between a couple other systems and this one and I feel relieved that I made the right decision. If your like me and you find yourself spending ridiculous amounts of time indecisively listening to exhuast systems online, I would just go with the Loudmouth. You won’t be disappointed.

  6. Rated 4 out of 5
    ( 18 reviews )

    Stevan velazquez (verified owner)

    Let me tell you this exhaust sounds awesome! I had a cutout before and sounded good but I dealt with alot of ridiculous drone, especially with AC on or around 1800-2000 RPM range; mainly because it dumped right under the car. The drone is minimal with Loudmouth and just sounds plain EVIL at wide open throttle. You can’t appreciate how good it sounds while driving, its all the cars driving next to you with the windows down or pedestrians that get the treat. I say that because it I had a buddy do a couple of drive bys for me and it sounds a hell of alot better as an outsider. The only downside is the band clamps I got didnt seal so well around the resonator, nothing that your local welder can’t fix.

  7. Rated 5 out of 5
    ( 18 reviews )

    Joseph Lutz II (verified owner)

    I bought this exhaust for my 96 Firebird Formula, and it sounds absolutely incredible. Everyone who hears it loves the way it sounds, and I definitely do as well. Quick and easy installation, and quick shipping too. This is the only exhaust I’ll run on any Firebirds I own from here on out. No more “slowmaster” mufflers. The one that I pulled off is already in the dumpster 😀 Thanks WS6 Store.

  8. Rated 5 out of 5
    ( 18 reviews )

    Shawn Bailey (verified owner)

    If you love loud and raw exhaust, this is the kit for you. Quite possibly the loudest setup short of open manifolds or headers I’ve ever heard. Fit is like it came from the factory with that. If you can tolerate a little “backtalk” from the exhaust on higher revs and letting off the gas, it sounds just downright nasty.

  9. Rated 5 out of 5
    ( 18 reviews )

    Jamie Boulanger (verified owner)

    very pleased with this purchase…i had a cut-out with a slowmaster muffler, sounded good, but there’s alot downsides with the cut-outs…the bottom of the car gets all black and dirty, and the interior had alot of rattling because it dumps out right under the car. i even connected a down pipe to the cutout and that didnt do much to solve those problems, and then the down pipe kept bumping the bottom of the car when i would go over bumps on the freeway, very annoying…as far as the slp loudmouth, it solved all those issues that i had, and its just as loud or even louder then the cut-out…i didnt use most of the band clamps except the one that connects to the y-pipe, so i had a muffler shop weld most of it together…and i must say the resonator and the tips look pretty sexy, well worth the money.

  10. Rated 5 out of 5
    ( 18 reviews )

    robert tate (verified owner)

    This exhaust is absolutely amazing!!! ricers cower in fear when they hear it at WOT! the roar after the install is loud like a beast!!! 🙂

  11. Rated 5 out of 5
    ( 18 reviews )

    Chris Rimmey (verified owner)

    Got it in the mail and had it on in just over an hour using a sawzall to cut the stock one out. I had a friend help me and it went very smoothly, and it sounds mean as hell. I’m very pleased with it and I would definitely recommend it to someone looking to upgrade, especially considering its cheaper than alot of the other exhausts.

  12. Rated 5 out of 5
    ( 18 reviews )

    Andrew Melton (verified owner)

    You want a loud roar? Get these. I bought them with my longtube headers and my LS1 completely came ALIVE! defently a head turner, everyone thinks its had head/cam work done. but its just a stock LS1 with a bite! Lovin’ this set-up. Highly recommended to people who wanna be heard!!!

  13. Rated 5 out of 5
    ( 18 reviews )

    Carlos castillo (verified owner)

    I had FlowMasters Before I bought These….I gotta Say This Exhuast Sounds way more BADASS, i felt the the difference rite away…..I Really Couldnt Be happier With my Purchase

  14. Rated 5 out of 5
    ( 18 reviews )

    Jeremiah Semonis (verified owner)

    I had a lot of hesitation towards purchasing this product, I had heard since it’s a straight pipe design that would cause a noticeable loss in low end torque, which is one of my favorite things about the LS1. After talking with many LM1 owners I finally decided to buy it, the shipping was fast, took only two business days. The install took an hour and a half, but the guy at the shop grossly overcharged me, charged me $200 for the install. Anyway, the install went on without a hitch, car drives completely the same, noticed no loss in torque, but it feels just a little bit quicker when I slam on it at 60MPH or higher. The car sounds like a whole different beast, everywhere I drive people will ALWAYS look over at me to see where all of that noise is coming from, it’s a good feeling because it sounds so sweet too. The drone inside the cabin was a bit louder than expected, right around 2,000 RPM you can feel the vibrations inside your chest, but it’s such a sweet sound and it gets VERY loud…you can hear the car coming from a mile away.

    Very pleased with my purchase, will buy from WS6 Store again. The K&N air charger kit is next.

  15. Rated 5 out of 5
    ( 18 reviews )

    Roy Lauth II

    I took a chance buying this exhaust since I heard it was very loud and was almost convinced to buy another brand. I am SOOO glad I didnt listen. I was VERY surprised at how quiet it is. It has just enough growl at 2500rpms and at lower rpms and cruising/highway speeds it is perfect and you can still have a normal conversation with passengers without having to yell.

    I have long tubes headers on the car now and it sounds even better. And as it was before 2,500rpms and above its a whole new animal!!

  16. Rated 4 out of 5
    ( 18 reviews )

    Jermias Santos (verified owner)

    Its loud at WOT but when crusing u can still play the radio and hold a conversation, also my LM1 is hooked up to American Racing long tubes with the catted Y, and when u get on it its CRAZY! but when im crusing between 75- 90 there is no drone at all, i can still play my music and talk and my phone, the only thing that sucks about this system is the tips, they are so ugly, i got the duals onmy T/A and i hate them, other than that, it bolted up great!

  17. Rated 4 out of 5
    ( 18 reviews )

    robert vass

    Have had my loudmouth 1 on for over a year and it still looks like new (no snow/salt). Installation wasnt that difficult although the clamps provided were not the best, one actually ripped apart before even getting tight what so ever on the inner pipe. The only other problem was the rear pipe (tail) wasnt level and couldnt for the life of me adjust the others to compensate for one being lower. Ended up having to stick a steel bar in one of the tails and “convincing” it to be even with the other.

  18. Rated 5 out of 5
    ( 18 reviews )

    Payton Christensen (verified owner)

    Sounds good not too loud like others say, Super easy install completed in about 20 minutes and 3 beers haha!

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SKU: 31042 Category: