Flowmaster Crossmember-Back Exhaust Kits for 1967-1970 Mustangs

Posted By: Stang-Aholics Staff

If you’re restoring or modifying a classic 1967–1970 Mustang, one of the most transformative upgrades you can make is a quality dual exhaust system. Flowmaster’s American Thunder Crossmember-Back exhaust kits are engineered to deliver deep, aggressive sound, improved throttle response, and bolt-in fitment designed specifically for these vintage Mustangs.

Here’s a deeper look at the four standout options we’re highlighting — with features, materials, style differences, and performance characteristics.

Product Details & Highlights

1. Crossmember Back Exhaust System w/ Turn-Downs

67‑70 Mustang Flowmaster Crossmember Back Exhaust System, w/ Turn Downs

  • Material: Aluminized steel

  • Exit Style: Turn-downs under rear valance

  • Sound: Moderate to aggressive exterior tone

  • Fitment: True dual system with built-in H-pipe

  • Best For: Traditional hot-rod look without valance cut-outs

Why it’s great: This system uses Flowmaster’s H-pipe balance and mufflers to give your Mustang an unmistakable rumble while exiting neatly with downward-angled pipes — perfect for show cars that want classic sound and style without cutting the rear valance.

2. Crossmember Back Exhaust System – Aluminized Steel with Polished Tips

67‑70 Mustang Flowmaster Crossmember Back Exhaust System, Aluminized Steel w/ Polished Tips

  • Material: Aluminized steel

  • Tips: 3.00″ polished stainless

  • Sound: Moderate to aggressive

  • Fitment: Fits through stock dual valance cut-outs

  • Best For: Classic dual tip look at an affordable price

Why it’s great: This kit keeps the classic Flowmaster tone and performance yet adds polished stainless tips for a more refined finish — ideal for enthusiasts who want that eye-catching shine along with a strong rumble.

3. Crossmember Back Exhaust System – Stainless Steel w/ Polished Tips

67‑70 Mustang Flowmaster Crossmember Back Stainless Exhaust System w/ Polished Tips

  • Material: Stainless steel (better corrosion resistance)

  • Tips: Polished stainless

  • Tone: Moderate to aggressive

  • Fitment: True dual w/ H-pipe, rear valance tips

  • Best For: Maximum durability with show-quality finish

Why it’s great: For the Mustang builder focused on long-term durability, stainless construction resists rust far longer than aluminized steel — a major advantage if you drive your Mustang regularly or in wet conditions.

4. Crossmember Back Exhaust System – Stainless Steel w/ Turn-Downs

67‑70 Mustang Flowmaster Crossmember Back Stainless Exhaust System, w/ Turn Downs

  • Material: Stainless steel

  • Exit Style: Turn-downs under rear valance

  • Tone: Moderate to aggressive

  • Fitment: Dual system w/ H-pipe design

  • Best For: Stainless durability with classic “street rod” exits

Why it’s great: Combining premium stainless materials with turn-down exits, this exhaust gives your Mustang both standout visuals and years of rust-resistant performance — all while retaining that full, deep Flowmaster sound.

Side-by-Side Comparison

Feature / Kit Turn-Down Aluminized Aluminized w/ Polished Tips Stainless w/ Polished Tips Stainless w/ Turn-Downs
Material Aluminized Steel Aluminized Steel Stainless Steel Stainless Steel
Exit Style Turn-downs Dual polished tip exit Dual polished tip exit Turn-downs
Sound Character Moderate → Aggressive Moderate → Aggressive Moderate → Aggressive Moderate → Aggressive
H-Pipe Balanced ✔️ ✔️ ✔️ ✔️
Valance Cut-Out Required No Yes Yes No
Best For Classic look, no valance cut Show car finish Premium durability Premium + classic position
Rust Resistance Medium Medium High High

Key Differences & Help Choosing

Material:

  • Aluminized Steel: Great performance and price — modest corrosion resistance. Ideal if you’re restoring a classic mainly for show or occasional drives.

  • Stainless Steel: Much better corrosion resistance for long-term use and frequent driving. Worth the investment if you care about longevity.

Exit Style:

  • Turn-down exits give a custom hot-rod style without cutting into your rear valance — a clean, traditional look.

  • Polished tip exits tuck through the stock dual cut-outs, giving the rear end a more OEM-inspired, finished appearance.

Tone & Performance:
All four systems use Flowmaster’s built-in H-pipe crossover and carefully matched mufflers (typically Super 44 Series), yielding a deep, muscular tone that’s louder and more aggressive than stock — perfect for Mustang V8 exhaust notes.

Installation & Compatibility Notes

  • These kits are true crossmember-back systems, meaning they replace everything from the rear crossmember back to the tips and include hangers & hardware for installation.

  • Some versions require dual valance cut-outs (the polished tip ones), while turn-down versions do not.

  • They do not include header reducers or manifold downpipes — you’ll need adapters if connecting to stock manifolds.

Final Thoughts

Flowmaster’s American Thunder Crossmember-Back exhaust systems are a go-to upgrade for ’67-’70 Mustang owners who want classic muscle-car sound, easy installation, and options that fit their style, durability, and budget needs. Whether you want a show-quality polished look or durable stainless performance, there’s an option ready to roar.

So are you ready to upgrade the sound and look of your Classic 67-60 Mustang? If you have decided you want to upgrade your classic Mustang with a Flowmaster exhaust, where you buy it matters just as much as what you buy.

When you’re building, upgrading, or maintaining a Mustang, expertise matters. Stang-Aholics.com isn’t just another parts website — it’s a destination built by Mustang enthusiasts for Mustang enthusiasts. That makes all the difference in the quality of parts you get, the advice you receive, and the confidence you have in every purchase. When you purchase your Flowmaster Exhaust Kit from Stang-Aholics.com, you’re not just clicking “add to cart” — you’re buying from real Mustang enthusiasts who live and breathe performance!

Product Image Gallery And Installed Photos

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