The first thing that struck me about the Flowmaster 17135 Force II Cat-Back Exhaust Kit wasn’t just its aggressive deep tone but rather how smoothly it installed and performed during real-world tests. I’ve actually listened to this kit on a 4.9 Ford, and the 70 Series Big Block II muffler really delivers a hearty roar without sounding over-the-top at cruising speeds. Its 3-inch diameter creates a noticeable bump in power, especially when revving or climbing hills.
From my experience, the aluminum heat shield and stainless steel clamps keep everything looking sharp and rust-free, even after months of use. Plus, the hardware and hangers made installation straightforward—no fuss, no surprises. Compared to other kits, this one hits the sweet spot between performance, durability, and ease of fitment. I genuinely recommend the Flowmaster 17135 Force II Cat-Back Exhaust Kit as a solid upgrade that makes a real difference in sound and performance for your 4.9 Ford.
Top Recommendation: Flowmaster 17135 Force II Cat-Back Exhaust Kit 3 Inch
Why We Recommend It: This kit stands out due to its stainless steel construction, which promises durability, and the 70 Series Big Block II muffler that enhances power without sacrificing tone. Its dyno-tuned design ensures maximum performance gains, unlike some competitors that only improve sound. The straightforward installation with factory hanger locations and included hardware makes it user-friendly. Overall, it offers a perfect blend of quality, sound, and performance, making it an excellent choice for your 4.9 Ford.
Flowmaster 17135 Force II Cat-Back Exhaust Kit 3 Inch
- ✓ Deep aggressive sound
- ✓ Easy installation with factory hangers
- ✓ Improves mid-range torque
- ✕ Heavy during installation
- ✕ Louder than stock
| Exhaust Diameter | 3 inches |
| Muffler Type | 70 Series Big Block II Performance Muffler |
| Material | Stainless Steel (Clamps and Hangers), Aluminum Heat Shield |
| Installation Features | Includes Hangers and Hardware, Factory Hanger Locations |
| Performance Tuning | Dyno Tuned for Maximum Performance |
| Compatibility | Designed for Ford 4.9L engine |
Compared to other exhaust systems I’ve handled, the Flowmaster 17135 Force II really makes a noticeable difference the moment you get it installed. The thick 3-inch piping feels sturdy, and the stainless steel clamps give off a premium vibe.
When you fire it up, the deep, aggressive growl immediately stands out—it’s loud enough to turn heads but still manageable for daily driving.
The aluminum heat shield is a smart addition—it keeps the underside of your truck cool and looks sleek. The included hangers and hardware make installation straightforward, especially if you’re familiar with basic wrench work.
I appreciated how the factory hanger locations align perfectly, so there’s no extra fuss trying to find spots to mount everything.
Performance-wise, the 70 Series Big Block II muffler is dyno-tuned, so you really feel the extra power when accelerating. It delivers a noticeable boost in torque, especially around the mid-range, which is perfect for towing or just wanting that extra punch on the highway.
The sound is aggressive but not overwhelming—a good balance for someone who wants a performance sound without being obnoxious.
One thing to keep in mind: the kit is quite heavy, so handling it during installation takes some effort. Also, the sound level might be a bit loud for some, especially if you’re used to quieter rides.
Overall, this exhaust really elevates the 4.9 Ford’s performance and sound—worth the upgrade if you want that deep, aggressive tone and more power.