If you’re like most automotive enthusiasts, the modification of your high performance street or strip vehicle begins with the removal of the stock exhaust to make way for a deeper-sounding, more powerful aftermarket exhaust system. And Flowmaster Mufflers, a name is which is synonymous with high performance exhaust and whose products emit a truly unmistakable tone, is quite commonly the go-to source to satisfy your high-horsepower needs.

With humble beginnings in 1983, founder Ray Flugger created Flowmaster’s first patented design of a silencer for race cars in an 800 square foot barn in Kenwood, California. What began as a mission to quiet race cars without a loss of horsepower evolved into designs and products able to not only quiet the vehicles, but increase horsepower and fuel economy and provide a great new sound as well. “Between all of those benefits, there are few products that you can put on your car that do all of those things in one easy bolt-on install,” says Flowmaster VP of Marketing Cam Benty.

Today, Flowmaster is comprised of three modern facilities in California and Idaho, employing over 250 workers. The company boasts the only exhaust research and development facility of it’s kind in the world – utilizing SuperFlow engine and chassis dynos to fine-tune the design and sound of its exhaust systems. The company’s modern line of mufflers are the result of years of development with racing engine builders, thousands of hours of research and development on the dyno, and real-world testing on the race track and the streets of America.

We recently tested five of Flowmaster’s latest and most popular performance mufflers for a sound comparison on a classic 1972 Chevrolet El Camino with a Pat Musi Performance 509 cubic inch engine under the hood. Producing over 600 tire-roasting horses, this El Camino is the perfect test bed for this collection of mufflers.

The lineup includes:

• 70 Series Big Block II
• 50 Series Delta Flow
• Super 44
• Super 40
• Super 10

70 Series

The 70 Series Big Block II Muffler is a three-chamber design, which incorporates a longer case for increased volume inside the muffler and lower sound levels. This muffler employs Flowmaster’s patented Delta Flow Technology which reduces interior resonance and increased efficiency, and is aimed for use on trucks, SUV’s, RV’s, tow vehicles, and high performance street cars such as our El Camino in which a quieter tone is desired. “This is one of our mildest mufflers that fits on a wide variety of applications, and if you can fit it on your vehicle, it’s one of the big choices these days,” said Benty.

While producing a much quieter tone than the other models we tested, the 70 Series still provides much-improved sound over the stock exhaust. The interior sound levels, as advertised, are very pleasant for those that prefer interior comfort while still catching the attention of those outside the car. In our tests, the 70 Series produced an average of 82 decibels at 3000 RPM from a distance of 30 feet.

• Three chamber design with longer case for increased volume inside the muffler and lower resonance
• Perfect for high performance street cars, most trucks, SUV’s, RV’s, and tow vehicles
• 82 decibels at 3000 RPM from a distance of 30 feet
• Soft interior tone
• Deep, distinct Flowmaster tone outside

50 Series Delta Flow

The 50 Series Delta Flow muffler – which was previously known as the 50 SUV. Intended for use on SUV’s and full-sized high performance street cars with larger displacement engines, the design and case size provides optimal exhaust flow, additional fuel mileage, and softer interior sound levels. Per Benty, “This is a really good classic muscle car muffler. Low restriction, not a lot of noise, great sound; there are a lot of great benefits, and it fits.”

In our tests, the 50 Series Delta Flow produced slightly more interior resonance than the 70 Series, while maintaining a comfortable level of sound for long commutes or weekend trips. The 50 Series Delta Flow produces a very distinctive, throaty sound at higher RPM, much as one would expect from a Flowmaster muffler.

• Three chamber design with increased case size for optimum exhaust flow, increased fuel economy, and reduced interior noise
• Made for all SUV’s and large displacement engines
• Throaty exterior tone with mellow, comfortable interior sound levels

Super 44

The Super 44 Series mufflers utilize Delta Flow Technology that delivers a strong, powerful tone, which the company boasts as the most aggressive, deepest sounding, highest-performing four-inch muffler that they’ve ever constructed. In addition to the sound, the Super 44 is designed for maximum durability; MIG-welded with 16-gauge aluminized steel or 409S stainless. The unit is 4 inches thick, 9.5 inches wide, and 13 inches long, with inlet sizes ranging from 2 to 3 inches to fit a myriad of late model and classic high performance and street automobiles.

Of the street mufflers that we tested, the Super 44 produced the highest interior and exterior tone for an experience to be enjoyed both inside and out that will surely catch the attention of anyone within earshot and provide the perfect addition to showcase the horsepower lurking under the hood.

• Two chamber muffler that incorporates same Delta Flow Technology found in larger Super 40 Series muffler
• High performance four-inch case street muffler with deep, rich tones
• Highest interior and exterior tone out of all tested street mufflers

Super 40

The Super 40 Series shares the same Delta Flow Technology as the Super 44, and was developed from Flowmaster’s Top Ten race muffler lineup for street and strip automobiles. The Super 40 is designed with a large, black case, limiting resonance while maintaining the exterior tone that the company is famous for. This muffler provides optimum performance for higher horsepower vehicles. “The Super 44 and the 40 are both aggressive-style mufflers with aggressive sound – more of a ‘race technology’ type of muffler. And they both fit a wide variety of different vehicles,” said Benty.

On our El Camino, the Super 40 emitted a mellow but deep tone at idle, while reaching to a throaty and aggressive tone at higher RPM. Inside, this muffler provided a great balance between sound and comfort, again with a mellow but distinctive sound.

The Super 40 is one Flowmaster’s best-selling mufflers, and for good reason.

• Provides best performance to higher horsepower vehicles
• Two chamber design that sports a black, oversize case to reduce resonance and maintain deep exterior tone
• Throaty and aggressive tone at higher RPM with mellow interior sound

Super 10

The most aggressive muffler in Flowmaster’s lineup and its newest, the Super 10 is aimed at (and best suited for) racing applications. “This muffler comes with all the benefits of race breeding, and is also very race-oriented. We say it’s an off road muffler, but what you use it for is up to your imagination,” explained Benty.

The Super 10 is engineered with the patented Delta Flow Technology found in the Super 40 and 44 Series mufflers, designed as a short, very small single chamber muffler constructed using 409S stainless steel for durability that is as close to an open pipe exhaust as one can get. The Super 10 is available in a variety of inlet/outlet combinations for different racing applications.

The Super 10 Series, as expected, produced the loudest, most aggressive sound levels both inside and out of the car. And while the volume levels were similar to that of open exhaust, the Super 10 series muffler provided the distinct Flowmaster tone.

Benty continued, “We’ve been trying to direct people to a more off road environment with that [Super 10], but one the things we hear is that they want a very, very aggressive muffler… You got it!”

• Suited to racing applications
• Utilizes Delta Flow technology found in Super 40 and Super 44 Series mufflers
• Comes with 10 year warranty
• Small, short, single-chamber muffler
• Deep, aggressive interior and exterior tone and volume close to that of open pipe exhaust

While these five options that we tested are well suited to many different high performance street and strip rides, Flowmaster offers a vast array of mufflers and exhaust systems to perk up nearly any application that a muffler can be installed on – from foreign and domestic automobiles to a myriad of 4WD and racing applications. “We have a lot of options. There’s a whole menu of mufflers that you can pick from, depending on your configuration, that will get you different levels of sound and performance,” Benty concluded.