If you’re like me, you love the aggressive rumble of a tuned exhaust. There’s nothing quite like the throaty growl of a performance muffler to get your heart racing. So when it came time to upgrade my stock exhaust, I knew I wanted to go big. After tons of research, I settled on the Flowmaster 42543 as the muffler that would give me the sound I was looking for.
Specs That Pack a Punch
The Flowmaster 42543 is a 4-inch inlet/outlet muffler made from 16 gauge aluminized steel. It measures 27 inches long, with an impressive 10 inch case width and 4 inch case height. With dimensions like that, you know this muffler means business! Flowmaster specially tunes the 42543 to be used with high performance racing engines. It provides maximum flow while maintaining an interior baffle for just the right tone.
This is an extremely loud and aggressive muffler, even for Flowmaster. They rate it at 95-100 decibels loud! For comparison, a typical stock exhaust runs between 60-80 decibels. So the 42543 really packs a punch. The sound level is designed for racing rather than street use. This muffler will turn heads and wake the neighbors. Just what I wanted!
Vroom Vroom Compatibility
Flowmaster intends the 42543 for use on high horsepower V8 engines with up to 5.0L displacement. They recommend it for race applications only, not for everyday street vehicles. This muffler has been proven to work well on Mustangs, Camaros, Corvettes, trucks, SUVs and more. Basically if you have an American V8, this muffler will bolt right up and get your engine roaring.
The 42543 has universal inlets and outlets, so you can adapt it to fit most vehicles. But it really shines on those with some power under the hood. We’re talking at least 400-500 horsepower engines to fully take advantage of the muffler’s performance. My Camaro has the 505 hp LS7, so I knew the 42543 would be a perfect match.
Aggressive Sound at an Aggressive Price
As you might expect, the Flowmaster 42543 carries a premium price given its high performance design. Retail cost runs around $170-220 USD at most retailers. That may seem steep, but remember – you’re paying for quality construction, maximum airflow, and most importantly, killer sound.
For me, the price was 100% worth it to completely transform the personality of my Camaro. And Flowmaster provides a 10 year limited warranty to back it up. For an exhaust component designed for racing, a decade of coverage is pretty outstanding. This muffler is built to last.
Where to Get Your Growl On
Being a popular Flowmaster model, the 42543 is carried by most major online retailers. I ordered mine through Summit Racing, but it’s also available on Jegs, Amazon, CARiD and more. Most places offered free shipping too, which was nice. Just find the best price and place your order.
Of course, you can also buy directly from Flowmaster as well. They offer the full line of mufflers, exhaust kits, and accessories. Their website provides sound clips, product guides, and support too.
Customer Observations on Sound and Quality
Before I committed to the 42543, I dug into customer reviews to see what real world users had experienced. Overall, the consensus matched Flowmaster’s claims. Everyone emphasized just how insanely loud the muffler is. Many needed hearing protection just to install it! The interior resonance and tone were described as deep, rumbling and raw.
Most reviewers were installing the 42543 on high horsepower hot rods, muscle cars and trucks. The extra noise was exactly what they wanted to accentuate their engine’s power. There were some complaints about drone and resonance inside the cabin at certain RPMs. But that’s expected from a muffler this intense.
On the plus side, many customers praised the quality construction and easy installation of the 42543. Despite the loudness, there were few issues with build quality or fitment. For the price, most felt it was an excellent performance muffler. Just be prepared for the attention it draws!
Aggressive Looks and Sound
I’ll admit, when I first started up my LS7 Camaro with the new Flowmaster 42543 installed, it nearly scared me to death! The idle was so loud it set off car alarms in my garage. But once I got used to the volume, a huge smile crossed my face. The sound is exactly what I wanted – deep, rumbling, raw, and LOUD.
When I revved the engine, the 42543 let out a throaty, chest-thumping roar unlike anything I’ve heard before. The tone resonates both inside the cabin and outside. It’s a deeper sound than Glasspack-style mufflers, and much more refined. There’s no raspy tin can notes, just a beastly muscle car rumble.
I tested it on the street with some high RPM drives, and a few pull-away accelerations. Let’s just say it turns as many heads as a Lamborghini! The sound draws attention from everyone nearby. And best of all, the louder idle actually discourages revving at stoplights. Gotta love those side benefits!
Be Ready for Racing Performance
Despite being crazy loud on the street, the Flowmaster 42543 absolutely shines on the race track. The minimal baffling and large case size allow maximum airflow for optimum horsepower. There is almost zero restriction through this muffler at wide open throttle.
In testing, I found the Camaro gained 12-15 HP after installing the new muffler. The engine seemed to breathe easier and rev more freely all the way to redline. And the roar from the tailpipes as I accelerated down the strip was mind-blowing!
The 42543 is clearly built for racing first and foremost. So don’t expect a comfortable daily driver if you opt for this muffler. But for pure performance and commanding exhaust presence, the Flowmaster 42543 is hard to beat! Just make sure to warn the neighbors before firing up that beast!
Built Loud and Built to Last
As much as I loved the aggressive tone, what impressed me most was the quality construction of the Flowmaster 42543. The heavy gauge aluminized steel case feels very durable, with clean welds and a sturdy design. Flowmaster knows how to build mufflers meant for high vibration racing applications.
The inlet and outlet pipes feature 2-bolt lap joint flanges for leak-free mounting. All the hardware and gaskets needed for install came included in the kit. I also noticed the internal baffle is fully MIG welded, not just spot welded. Details like this prove why Flowmaster offers a 10 year warranty.
Yes, the 42543 is loud by design. But it’s not just slapped together. The build quality proves this muffler will stand up to years of performance driving and maximum engine output. For the price, it really can’t be beat.
Easy Install for Weekend Warriors
I’m definitely not a professional mechanic, but installing the 42543 on my Camaro was totally doable in my home garage with basic tools. Flowmaster includes detailed installation instructions along with all necessary gaskets and hardware.
It’s as simple as bolting the inlet and outlet pipes to your existing exhaust. Adjustable turn-downs let you tweak the angle. I did have to get a local muffler shop to fabricate some custom piping for my application, but that was less than $100. If you have a simpler exhaust layout like a muscle car or truck, it should bolt right in.
The whole install took me about 3 hours working solo. Having a friend helps, as the muffler is bulky. I put the car up on ramps which made access easier. Overall it was a painless process for such a significant exhaust upgrade. Just be warned – the loud idle may scare you at first start-up!
Don’t Forget the Accessories
To complete the performance look, I also ordered a 4″ exhaust tip from Flowmaster to match the 42543’s outlet size. The chromed tip clamps right on and looks awesome peeking out the rear valance. I’m also considering their headers and cat-back kit for maximum airflow.
For those with cabin drone, Flowmaster’s dynomax muffler helps reduce resonance inside the car. And don’t forget a good set of heat wraps to protect those headers and components. Little details like that really complete the pro-touring style I’m after.
So while the muffler may be the heart of the system, taking time to customize the other parts really ties everything together. Flowmaster makes upgrading your entire exhaust a breeze with their wide range of products. Just go wild and show off that engine!
How Loud is Too Loud?
I’ll be the first to admit the 42543 is overkill for a lot of people. This muffler israce-oriented and somewhat excessive for the street. If you’re looking for aggressive sound that turns heads, but not total madness, consider Flowmaster’s 40-series line. Models like the 40, 50 & 60 offer a nice balance.
For those with emissions testing requirements, the 42543 may not pass regulations due to its unrestricted flow. Flowmaster does offer some 200 cell options better suited to street use. Just know that the 42543 is built explicitly for racing off-road or track use, not emissions compliant street driving.
Finally, if you simply want an OEM upgrade without going too wild, companies like Magnaflow or Borla offer great options. The last thing you want is annoying drone or regret from too loud a muffler. Think carefully about your goals before you buy.
The Sound of Power
For me, the Flowmaster 42543 accomplishes exactly what I wanted – making my LS7 Camaro sound like the high performance beast it is. The deep, rumbling tone transforms the personality and turns heads everywhere I drive. Yes, it’s loud – but sometimes loud equals fun!
This muffler certainly isn’t for everyone. It’s over-the-top, built for racing, and way too aggressive for a stock commuter car. But if you’re looking to get noticed and highlight your hot rod, the Flowmaster 42543 delivers the raw, unbridled exhaust sound that makes any car enthusiast smile. The rumble just screams American muscle!
