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Flowmaster 817158 - American Thunder Header Back Exhaust System

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$593.95

$659.95

You save: $66.00 (10%) off MSRP

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This part fits

  1. 1974 Pontiac Ventura
  2. 1973 Chevrolet Nova 4.1L L6 cid:250
  3. 1973 Pontiac Ventura
  4. 1973 Chevrolet Nova 5.0L V8 cid:307 cc:5031
  5. 1973 Chevrolet Nova 5.0L V8 cid:307
  6. 1973 Chevrolet Nova 4.1L L6 cid:250 cc:4098
  7. 1973 Chevrolet Nova 5.7L V8 cid:350
  8. 1973 Chevrolet Nova 4.1L L6 cid:250 cc:4097
  9. 1972 Chevrolet Nova 5.0L V8 cid:307 cc:5031
  10. 1972 Pontiac Ventura
  11. 1972 Chevrolet Nova 4.1L L6 cid:250 cc:4097
  12. 1972 Chevrolet Nova 4.1L L6 cid:250
  13. 1972 Chevrolet Nova 4.1L L6 cid:250 cc:4098
  14. 1972 Chevrolet Nova 6.6L V8 cid:402 cc:6588
  15. 1972 Chevrolet Nova 5.0L V8 cid:307
  16. 1972 Chevrolet Nova 5.7L V8 cid:350
  17. 1971 Pontiac Ventura 5.7L V8 cid:350 cc:5733
  18. 1971 Pontiac Ventura 5.0L V8 cid:307 cc:5031
  19. 1971 Chevrolet Nova 5.0L V8 cid:307 cc:5031
  20. 1971 Chevrolet Nova 5.0L V8 cid:307
  21. 1971 Pontiac Ventura 5.0L V8 cid:307
  22. 1971 Chevrolet Nova 7.4L V8 cid:454 cc:7439
  23. 1971 Chevrolet Nova 6.6L V8 cid:402 cc:6588
  24. 1971 Chevrolet Nova 5.7L V8 cid:350
  25. 1970 Chevrolet Nova 7.4L V8 cid:454 cc:7439
  26. 1970 Chevrolet Nova 5.0L V8 cid:307
  27. 1970 Chevrolet Nova 6.5L V8 cid:396
  28. 1970 Chevrolet Nova 6.6L V8 cid:402 cc:6588
  29. 1970 Chevrolet Nova 5.0L V8 cid:307 cc:5031
  30. 1970 Chevrolet Nova 5.7L V8 cid:350
  31. 1969 Chevrolet Nova 5.7L V8 cid:350
  32. 1969 Chevrolet Nova 5.0L V8 cid:307 cc:5031
  33. 1969 Chevrolet Nova 6.5L V8 cid:396
  34. 1969 Chevrolet Nova 5.0L V8 cid:307
  35. 1969 Chevrolet Nova 6.5L V8 cid:396 cc:6489
  36. 1968 Chevrolet Chevy II 6.5L V8 cid:396 cc:6489
  37. 1968 Chevrolet Chevy II 6.5L V8 cid:396
  38. 1968 Chevrolet Chevy II 5.4L V8 cid:327
  39. 1968 Chevrolet Chevy II 5.0L V8 cid:307
  40. 1968 Chevrolet Chevy II 5.3L V8 cid:327 cc:5358
  41. 1968 Chevrolet Chevy II 5.0L V8 cid:307 cc:5031
  42. 1968 Chevrolet Chevy II 5.7L V8 cid:350
  43. show all...
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About this product

Part #: 817158

For the person who is looking for a complete Header-back dual exhaust system with an aggressive tone. These systems are mandrel bent for maximum performance and include specially selected mufflers. American Thunder systems deliver a moderate to aggressive interior and exterior tone and are suited to the enthusiast who wants their performance to be heard. Like all Flowmaster systems, the benefits include improved throttle response, power and mileage. Designed for an easy fit, these systems include all necessary parts and hardware for easy installation.

More Details

Exhaust SeriesAmerican Thunder
Exhaust TypeDual
Exit PositionDual Rear
Exit StyleStraight
Heat Shield AttachedNo
Inlet Diameter2.500 in.
Inlet Inside Diameter2.500 in.
MaterialStainless Steel
Muffler Count2
Muffler Part NumberKit Only
Muffler SeriesSuper 44 Series
Outlet Diameter2.500 in.
Outlet Outside Diameter2.500 in.
Single or DualSingle
Sound LevelModerate/Aggressive
System TypeHeader Back
Tail Pipe Diameter2.500 in.
TitleFlowmaster 817158 Header-back System 409S -Dual Rear Exit - American Thunder - Moderate/Aggressive
Tubing Diameter2.500 in.
Additional Documents
  1. Certificate of Originpdf
  2. Installation Instructionspdf
  3. Warrantypdf

See what our community says about flowmaster products

product page reviews icon 0product page reviews icon 1product page reviews icon 2product page reviews icon 3product page reviews icon 4
What made you choose this particular product?
Wanted something loud and raspy
Is this your first time buying from this brand? Did you consider other brands?
Yes like carven r or a black widow
Was it easy to install? Any installation tips that will help others?
Had a muffler shop weld it on
Once you've had a chance to use the product, did it meet your expectations?
Sounded like a v8 supposed to sound
Any additional comments?
Also a cat delete and 5" exhaust tips
View on Luis's build
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What made you choose this particular product?
Performance
View on Tony's build
product page reviews icon 0product page reviews icon 1product page reviews icon 2product page reviews icon 3product page reviews icon 4
What made you choose this particular product?
Quality and familiarity with sound.
Is this your first time buying from this brand? Did you consider other brands?
No
Was it easy to install? Any installation tips that will help others?
A little cumbersome on the garage floor, but very straight forward and fairly simple (exception of left side fixed bolt bracket from existing pro chamber :o ).
Once you've had a chance to use the product, did it meet your expectations?
Yes.
Any additional comments?
I sought a sound change toward something a little less aggressive. I never knew what exactly the existing cat back brand was. They were (well, I still have them in the garage) quality built, but very aggressive,, maybe 1 chamber in each muffler albeit thin. The sound went from a rabid crackle to a now lower tone rumble. Aggressive cam sound with the stroke and metallic courtesy sound from headers are all still there. ;)
View on Adm's build
product page reviews icon 0product page reviews icon 1product page reviews icon 2product page reviews icon 3product page reviews icon 4
What made you choose this particular product?
Had em before
View on Brock's build
product page reviews icon 0product page reviews icon 1product page reviews icon 2product page reviews icon 3product page reviews icon 4
What made you choose this particular product?
This product gives you that fantastic and aggressive sound you expect out of a muscle car. Highly recommend for anyone who wants to add a bit of growl to their ride!
Is this your first time buying from this brand? Did you consider other brands?
This is my first time buying from Flowmaster and I considered corsa as an alternative before settling on the Flowmasters.
Was it easy to install? Any installation tips that will help others?
I had them professionally installed.
Once you've had a chance to use the product, did it meet your expectations?
They sounded exactly how I wanted them to sound. I was overjoyed!
Any additional comments?
They do drone a bit during MDS activation and in the 2.2k rpm range. I would recommend 12inch cherry bomb glasspack mufflers to use in place of the resonators to tone down the drone while maintaining the impressive sound. Your mileage and preferences may vary.
View on Charles's build
California prop 65 warningWARNING: Cancer and Reproductive Harm www.p65warnings.cs.gov

*Some manufacturer restrictions apply.

About Flowmaster

Manufacturer of performance exhaust systems, mufflers, cold air intakes, turbo boost modules, catalytic converters, race mufflers, headers and numerous exhaust accessories for late model cars, trucks, off-road, Jeeps, SUV’s, classic muscle cars, powersports vehicles and more. Flowmaster® gives you lots of exhaust choices with 12 designs of chambered mufflers, 3 styles of our exclusive “laminar-flow” mufflers and a new line of FlowFX “straight-through” performance mufflers, along with 5 sound categories of exhaust systems, giving you the customer, the power to custom tailor the sound of your vehicle whether you prefer mild, moderate or aggressive tones and sound levels.

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