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Doug Thorley Tri-Y Headers


Doug Thorley
Doug Thorley Tri-Y Headers

Product images may differ from actual product appearance.

The Tri-Y was invented by Doug Thorley Headers and is designed to match the synchronization of the engine's firing order, thus maximizing exhaust scavenging.

Doug Thorley Tri-Y Headers create optimum torque and the greatest horsepower gains in comparison to any other design. They yield maximum power from idle to 4500 RPM while adhering to strict emissions standards. Engineered to be well-suited for multiple applications, power significantly increases at mid-range RPM for exceptional efficiency at highway speeds. Fuel economy and low-end torque are improved; back pressure, engine heat, and weight are all reduced.

  • 14-gauge steel tubing and 3/8" flanges
  • Easy installation
  • 50-state legal



  • 18 Products
    Ford

    702-214Y-FI3-C
    Tri-Y Header
  • 1993.5-1995 Ford 460 Class C Motorhome
  • Ceramic Coated
  • 1-3/4" Primaries
  • 2-1/2" Collector
    More info on Doug Thorley 214Y-FI3-C
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    Installation Instructions for Doug Thorley 214Y-FI3-C
  • $769.99
    Ships
    General Motors

    702-300Y-C
    Tri-Y Header
  • 1961-66 GM Pickup/Truck 283-400
  • 1973-87 GM Pickup/Truck 283-400
  • Ceramic Coated
  • 1-5/8" Primaries
  • 2-1/2" Collector
    More info on Doug Thorley 300Y-C
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    MPG
  • $631.99
    Order Today Ships 05/01/14
      702-300Y-DA
    Tri-Y Header
  • 1961-66 GM Pickup/Truck 283-400
  • 1973-87 GM Pickup/Truck 283-400
  • With Dual Air Injection
  • Chrome Finish
  • 1-5/8" Primaries
  • 2-1/2" Collector
    More info on Doug Thorley 300Y-DA
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    MPG
  • $555.99
    Order Today Ships 05/01/14
      702-300Y-DA-C
    Tri-Y Header
  • 1961-66 GM Pickup/Truck 283-400
  • 1973-87 GM Pickup/Truck 283-400
  • With Dual Air Injection
  • Ceramic Coated
  • 1-5/8" Primaries
  • 2-1/2" Collector
    More info on Doug Thorley 300Y-DA-C
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    MPG
  • $639.99
    Order Today Ships 05/01/14
      702-300Y-S
    Tri-Y Header
  • 1961-66 GM Pickup/Truck 283-400
  • 1973-87 GM Pickup/Truck 283-400
  • With Single Air Injection
  • Chrome Finish
  • 1-5/8" Primaries
  • 2-1/2" Collector
    More info on Doug Thorley 300Y-S
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    MPG
  • $569.99
    Order Today Ships 05/01/14
      702-300Y-S-C
    Tri-Y Header
  • 1961-66 GM Pickup/Truck 283-400
  • 1973-87 GM Pickup/Truck 283-400
  • With Single Air Injection
  • Ceramic Coated
  • 1-5/8" Primaries
  • 2-1/2" Collector
    More info on Doug Thorley 300Y-S-C
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    MPG
  • $652.99
    Order Today Ships 05/01/14

    702-303Y-DA-C
    Tri-Y Header
  • 1975-00 Class A Motorhome P-30 Chassis Only
  • 1973-1987 Truck/Suburban/Blazer/Jimmy 366-454 2WD
  • With Dual Air Injection
  • Ceramic Coated
  • 1-3/4" Primaries
  • 2-1/2" Collector
    View this item
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  • $655.99
    Order Today Ships 05/01/14

    702-310Y-1-C
    Tri-Y Header
  • 1999-12 Truck/Suburban/Tahoe/Yukon/Escalade/Denali
  • 4.8L-6.2L, 2/4WD, Off-Road Only (No Smog Fittings)
  • Ceramic Coated
  • 1-5/8" Primaries
  • 3" Collector
    More info on Doug Thorley 310Y-1-C
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  • $589.99
    Order Today Ships 05/01/14

    702-333Y-C
    Tri-Y Header
  • 2008 G8 GT 6.0L LS2
  • Ceramic Coated
  • 1-3/4" Primaries
  • 2-1/4" Collectors
    More info on Doug Thorley 333Y-C
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    MPG
  • $655.00
    Order Today Ships 05/01/14

    702-337Y-C
    Tri-Y Header
  • 2010-11 Camaro SS 6.2L LS3/L99
  • Ceramic Coated
  • 1-3/4" Primaries
  • 2-1/4" Collectors
    More info on Doug Thorley 337Y-C
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    Dyno Chart for Doug Thorley 337Y-C MPG
  • $726.00
    Order Today Ships 05/01/14

    702-375Y-C
    Tri-Y Header
  • 1967-78 Camaro 265-400
  • 1968-77 Nova 265-400
  • 1968-78 Chevelle/El Camino 265-400
  • Ceramic Coated
  • 1-5/8" Primaries
  • 2-1/2" Collectors
    More info on Doug Thorley 375Y-C
    • FREE
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    MPG
  • $607.00
    Order Today Ships 05/01/14
    Jeep/American Motors
      702-630Y-C
    Tri-Y Header
  • 1993-99 Grand Cherokee 318/360
  • Ceramic Coated
  • 1-5/8" Primaries
  • 2-1/2" Collector
    More info on Doug Thorley 630Y-C
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    MPG
  • $779.99
    Order Today Ships 05/01/14
    Suzuki
      702-700Y-C
    Tri-Y Header
  • 1983-95 Samurai/Sidekick/Geo Tracker 4WD 1.3L-1.6L 8V
  • Ceramic Coated
  • 1-1/2" Primaries
  • 2-1/2" Collector
    View this item
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    MPG
  • $382.99
    Order Today Ships 05/01/14

    702-THY-716Y-C
    Tri-Y Header
  • 1992-99 Samurai/Sidekick/Geo Tracker 4WD 1.3L-1.6L 16V
  • Ceramic Coated
  • 1-1/2" Primaries
  • 2-1/2" Collector
    View this item
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  • $374.99
    Order Today Ships 05/01/14
    Toyota
      702-542Y-SO
    Tri-Y Header
  • 1981-84 Toyota Pickup 2/4WD 20R/22R
  • 1984.5-87 4Runner 2/4WD 20R/22R
  • SMOG Fittings & O2 Bung
  • Chrome Finish
  • 1-1/2" Primaries
  • 2-1/4" Collector
    More info on Doug Thorley 542Y-SO
    • FREE
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    MPG
  • $381.00
    Order Today Ships 05/01/14
      702-542Y-SO-C
    Tri-Y Header
  • 1981-84 Toyota Pickup 2/4WD 20R/22R
  • 1984.5-87 4Runner 2/4WD 20R/22R
  • SMOG Fittings & O2 Bung
  • Ceramic Coated
  • 1-1/2" Primaries
  • 2-1/4" Collector
    More info on Doug Thorley 542Y-SO-C
    • FREE
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    MPG
  • $456.99
    Order Today Ships 05/01/14

    702-555Y-C
    Tri-Y Header
  • 1988-95 Toyota Pickup 2/4WD 20R/22R
  • Ceramic Coated
  • 1-1/2" Primaries
  • 2-1/4" Collector
    More info on Doug Thorley 555Y-C
    • FREE
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    MPG
  • $410.00
    Order Today Ships 05/01/14

    702-560Y-C
    Shorty Tri-Y Header
  • 2007-08 Tundra 2/4WD 5.7L
  • Ceramic Coated
  • 1-5/8" Primaries
  • 2-1/2" Collector
    View this item
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    MPG
  • $730.00
    Order Today Ships 05/01/14

    18 Products