KJ Jones
Brand Manager, 5.0 Mustang & Super Fords
June 1, 2010
Photos By: KJ Jones

On the Dyno
Going into this project, we knew that adding long-tube headers and 3-inch exhaust pipes would promote a nice torque gain for Sean's already torquey '08 Shelby GT500. However, the big surprise was the increased horsepower we saw with the addition of Kooks' long tubes, and a little SCT tuning that was handled by our friend Lance Keck.

It's important to note that while the peak-power number achieved with the headers does look insane, it is derived using a baseline peak of 604.82/538.16. The lower numbers reflects the true, SAE, on-the-ground horsepower and torque (according to a Dynojet chassis dyno) that the GT500 had on tap as Sean drove it around with the bone-stock exhaust.

However, the bottom line is that the Kooks exhaust system and sharp tuning made an impressive performance gain on Sean's mega-blown Shelby, and it opens the door for easily going straight to the engine's threshold, with the addition of higher-octane fuel and tuning.

BaselineKooksDifference
RPMHPTQA/FHPTQA/FHPTQA/F
3,000280.22491.4311.40304.27532.6411.6724.0541.210.27
3,100284.77482.8311.20315.97535.3611.6531.2052.530.45
3,200302.28496.3311.20327.98538.2711.7125.7041.940.51
3,300313.64499.2511.20342.14544.5411.6528.5045.290.45
3,400325.65503.0211.10354.15547.0511.6328.5044.030.53
3,500331.79497.8411.10367.90552.0711.6936.1154.230.59
3,600349.35509.6111.20381.14556.0411.6331.7946.430.43
3,700355.74504.9711.40391.75556.0711.7936.0151.100.39
3,800374.45517.5411.50408.96565.2211.8434.5147.680.34
3,900386.88521.0311.50424.32571.4411.9037.4450.410.40
4,000397.75522.2711.50434.09569.9711.8136.3447.700.31
4,100406.16520.2611.40447.64573.4011.7141.4853.140.31
4,200422.81528.7011.50465.38581.9611.7342.5753.260.23
4,300436.33532.9411.60477.05582.6811.7340.7249.740.13
4,400446.21532.6311.70492.04587.3211.8545.8354.690.15
4,500461.09538.1611.70506.57591.2211.7545.4853.060.05
4,600468.89535.3611.50516.17589.3611.7347.2854.000.23
4,700479.63535.9511.50528.43590.5011.7348.8054.550.23
4,800488.33534.3511.50539.09589.8611.6550.7655.510.15
4,900501.15537.1611.60553.58593.3511.6552.4356.190.05
5,000508.07533.6911.60561.16589.4711.5953.0955.78-0.01
5,100520.76536.2911.40568.44585.4111.7347.6849.120.33
5,200525.91531.1911.30575.57581.3311.7549.6650.140.45
5,300537.06532.2011.40587.01581.7111.6349.9549.510.23
5,400546.45531.4911.50597.69581.3211.7151.2449.830.21
5,500555.31530.2911.70601.52574.4411.5946.2144.15-0.11
5,600563.56528.5711.80610.73572.7811.5747.1744.21-0.23
5,700566.99522.4411.80616.00567.6111.5749.0145.17-0.23
5,800574.77520.4711.70625.61566.5211.6150.8446.05-0.09
5,900582.49518.5311.80627.21558.3311.6344.7239.80-0.17
6,000587.66514.4211.90632.47553.6411.7944.8139.22-0.11
6,100594.80512.1211.90638.32549.60 0.0043.5237.48-11.90
6,200597.45506.1212.00640.77542.82 0.0043.3236.70-12.00
6,300597.97498.5212.00649.06541.10 0.0051.0942.58-12.00
6,400600.05492.4411.90651.38534.55 0.0051.3342.11-11.90
6,500600.74485.4212.00657.40531.21 0.0056.6645.79-12.00
6,600604.82481.3111.90653.86520.50 0.0049.0439.19-11.90