2009-2018 Ram 1500 5.7L Cat-Back: MBRP vs Flowmaster

A cat-back exhaust is the single most satisfying bolt-on you can add to a 2009–2018 Ram 1500 5.7L HEMI, and picking the right one comes down to three proven systems: the MBRP 3-inch T409 stainless, the Flowmaster FlowFX Extreme, and the Gibson Patriot Skull Series. Your factory 5.7L already makes 390–395 horsepower and 407–410 lb-ft, but it breathes through a restrictive, soft-sounding muffler. Swap in a true cat-back and you wake up that HEMI rumble, shave a little weight, and free up a few honest horsepower. At our Tampa, FL shop these three are the systems Ram owners ask for by name, so we lined them up side by side.

How much does a cat-back add to a 5.7L HEMI Ram 1500?

A cat-back exhaust on the 5.7L HEMI typically frees up roughly 5–15 horsepower and torque, according to each manufacturer's dyno claims — the real payoff is sound, throttle response, and a small bump in efficiency. A cat-back replaces everything from the catalytic converter back: the intermediate pipe, the muffler, and the tailpipe. Because it lives downstream of the cats, it keeps your truck 50-state emissions legal and does not touch the factory computer.

The factory 2009–2018 Ram 1500 5.7L HEMI pushes exhaust through a 2.5-inch system with a heavy, baffled OE muffler tuned for silence. Stepping up to a mandrel-bent 3-inch cat-back lowers backpressure and exhaust gas temperature, which is why Flowmaster and MBRP both advertise modest power and fuel-economy gains. Be honest with your expectations: you are buying this for the sound and the look first, and the dyno gains second. Flowmaster, for example, publishes gains of up to 13 hp and 14 lb-ft at the rear wheels for the FlowFX Extreme, while MBRP quotes figures in the 5–7 range — all manufacturer numbers, not independent tests.

MBRP vs Flowmaster vs Gibson at a glance

Here is how the three cat-backs stack up for the 2009–2018 Ram 1500 5.7L HEMI. All three are mandrel-bent, use factory hanger locations for a bolt-on install, and carry a lifetime warranty. The biggest differences are material, exit style, sound character, and price.

*The Flowmaster FlowFX Extreme fits 2009–2018 trucks as well as 2019–2024 Ram 1500 Classic (old-body) models and 2009–2014 4.7L V8s. Always confirm your exact year, engine, and cab before ordering.

MBRP 3-inch T409 cat-back: our top pick

The MBRP single-side cat-back is the best all-around choice for the 2009–2018 Ram 1500 5.7L HEMI because it balances an aggressive-but-livable tone, genuine rust-proof T409 stainless steel, and a mid-pack price around $595. It runs 3-inch mandrel-bent tubing from the cat back into an MBRP performance muffler and exits single-side in front of the rear tire. T409 stainless is the key detail here: it shrugs off the salt, slush, and humidity a daily-driven truck sees, so the system looks and performs like new for years.

Flowmaster FlowFX Extreme: the best value

The Flowmaster FlowFX Extreme is the smart-money pick for the 2009–2018 Ram 1500 5.7L: it delivers Flowmaster's signature deep tone for around $415 — the lowest price of the three. It uses 3.0-inch, 16-gauge mandrel-bent 409 stainless tubing and the FlowFX series muffler, then runs a turndown "dump" exit right after the muffler instead of routing a pipe over the rear axle. Deleting that over-axle tailpipe actually improves ground clearance and departure angle, which off-road and lifted-truck owners appreciate.

Gibson Patriot Skull: boldest looks and sound

The Gibson Patriot Skull Series is for the Ram owner who wants to be seen as well as heard. It is a stainless-steel single cat-back topped with a huge 6-inch black Cerakote exhaust tip — a genuine statement piece that looks nothing like a factory pipe. Gibson tunes the Patriot Skull louder and more aggressive than its usual lineup, yet owners consistently report it keeps highway drone in check. At around $730 it is the priciest of the three, but the 4-inch system and that oversized Cerakote tip back up the price with real presence.

Sound: what each cat-back actually sounds like

All three cat-backs make the 5.7L HEMI noticeably deeper and more aggressive than stock, but their personalities differ. The MBRP is the best balance — a mean, muscular growl when you get on it and near-stock quiet at a 70 mph cruise, which is why it is our everyday pick. The Flowmaster FlowFX Extreme leans on Flowmaster's classic deep tone; owners of newer trucks describe it as close to factory-quiet at cruise with a pleasant burble, then loud and purposeful under load. The Gibson Patriot Skull is the loudest and most in-your-face, built to turn heads, yet Gibson engineered it to keep interior drone down.

Drone — that resonant cabin hum at steady highway speeds — is the number-one complaint HEMI owners raise, so every system here was chosen partly because owners report it stays manageable. If a whisper-quiet cab is your priority, the MBRP or Flowmaster is the safer bet; if you want everyone at the stoplight to look, the Gibson delivers.

Installing your Ram 1500 cat-back: what to expect

Installing a cat-back on the 2009-2018 Ram 1500 is a genuine driveway job that most owners finish in 1–2 hours with hand tools. Because all three systems here are direct bolt-on and reuse the factory rubber hangers, there is no welding, no cutting, and no tune required. The hardest part is usually breaking loose the single factory clamp behind the muffler, so soak it with penetrating oil the night before and keep a propane torch or breaker bar handy if your truck has spent time in the salt belt.

Raise the rear of the truck on jack stands, support the factory exhaust, and remove the OE clamp at the intermediate pipe. The old muffler and tailpipe section slides off the hangers; the new system slides on in the same spots. Hang everything loosely first, align the tip (or turndown, on the Flowmaster) so it sits where you want relative to the bumper and tire, then torque the band clamp. Take a short drive and re-check the clamp and hanger alignment after the system heats up and settles — a five-minute step that prevents rattles and uneven tips. First-timers tell us the MBRP and Gibson tip-exit systems are the most forgiving to align, while the Flowmaster's turndown is the quickest because there is no over-axle tailpipe to route.

Which cat-back should you put on your HEMI?

Choose the MBRP if you want the best all-around cat-back and plan to keep the truck for years — the T409 stainless and balanced tone make it the safe, do-it-all choice at around $595. Choose the Flowmaster FlowFX Extreme if price is your priority or you run a lift and want the clearance of a turndown exit; at roughly $415 it is our clearly labeled budget pick and the best sound-per-dollar in this group. Choose the Gibson Patriot Skull if you want the boldest look and the loudest bark and don't mind spending around $730 for that 6-inch Cerakote tip.

Whichever you pick, all three bolt on in an afternoon with hand tools using the factory hanger locations, keep your Ram emissions-legal, and are in stock and ready to ship from NLP Performance. Pair any of them with a cold air intake for a little extra throttle response, and you have the two most popular HEMI bolt-ons done.