How to Build an 8-Second S650 Mustang

Our 2024 Mustang Dark Horse is not a trailer queen. It is a real, street-driven S650 that we took down the quarter mile at 8.87 at 154 mph, running the Gen 4 5.0L Coyote that still cold-starts on the button and idles like a factory car.

Getting there takes roughly 1,000 rear-wheel horsepower put down cleanly, and the naturally aspirated 5.0L will not make that on its own. Below we break the build down category by category and flag every part we actually bolted to the car, so you can copy the combination or scale it to your own power goal. This works whether you drive a GT or a Dark Horse.

Watch the full build come together in the video, then use the section links above to jump straight to what you are shopping for.

A Gen 4 Coyote making 8-second power moves a lot of fuel, and the factory system runs out of headroom long before you see 1,000 rwhp. Plan on a high-capacity fuel system with a PWM-controlled pump setup and a set of larger injectors so you can hold safe air-fuel ratios under full boost. This matters even more on E85, which needs roughly 30 percent more volume than 93 octane to make the same power.

Start with our Lethal Performance / DivisionX Fuel System Guide to match a system to your power target, then size injectors to the fuel you plan to run. We fed our 8-second Dark Horse with KPM PWM fueling and Injector Dynamics injectors.

Most supercharger kits ship with a base calibration, and it will get you running. It will not get you into the 8s. Once you add fueling, a smaller pulley, headers, and more boost, you need a custom tune written for your exact combination to safely command timing, boost, and fuel across the whole map.

We run the Lethal Performance RTD4 by HP Tuners, which hands the tuner full real-time data (RTD) access to adjust the car datalog by datalog. Pick your calibrator from The Tune Shop. We only work with tuners who have actually put S650s into the 8s.

Boost is where the S650 wakes up. We chose a Whipple Gen 6 3.0L twin-screw because it delivers instant low-end torque and Whipple keeps pushing its cooling and efficiency gains down through the whole lineup, so even earlier model years benefit.

Twin-screw blowers like Whipple, Roush, and VMP sit on top of the engine and make big torque right now. A centrifugal ProCharger mounts up front, builds boost with rpm, and rewards top-end pulls. Both will run 8s with the right supporting parts. Still deciding? Read our breakdown of the top-selling supercharger brands.

Once the blower is feeding the engine, you want the spent gases out with as little restriction as possible. A set of long-tube headers plus a cat-back is the classic move: the headers scavenge exhaust from the Gen 4 Coyote to free up real power, and the cat-back sets the tone.

We actually ran gutted factory manifolds on our 8-second pass, which tells you how much the rest of the combination is doing, but a set of Kooks 1-7/8 long-tube headers would only help. Behind that, choose a cat-back from AWE, Corsa, Borla, MagnaFlow, or MBRP based on how loud you want to be. Hear the AWE SwitchPath exhaust before you commit.

Making the power is one thing. Surviving the launch is another. The S650 comes with either the 10R80 automatic or the Tremec TR-3160 six-speed manual, and both need attention before they see 8-second slips.

On the manual, the clutch is the first thing to give. Step up to a twin-disc rated for the power, like the Lethal Performance LPXHD or the McLeod RXT and RXT-HD. A twin-disc holds four-digit torque without turning your left leg into a workout.

The 10R80 automatic is the easier path to consistent 8s once it is built. We had ours done by our friends at RSA Race Solutions, but we stock plenty of clutch-pack upgrade kits ready to handle the power. Pair that with a forced-induction torque converter and the trans will take hard launches and repeat quarter-mile passes.

The independent rear suspension on the S650 puts all of that power through half-shafts and a driveshaft that were never designed for 1,000 rwhp launches on a sticky tire. Reinforce the driveline before you break something expensive.

We learned the hard way on our old S550 that stock axles snap, and it is never fun. Upgrade to units built for abuse from GForce Performance or Driveshaft Shop, with options rated well past 2,000 horsepower.

A one-piece carbon or aluminum driveshaft holds more power and drops rotating weight, which helps trap speed. The QA1 carbon shaft we ran is no longer produced, but we still stock carbon and aluminum options for both the 10R80 automatic and the TR-3160 manual.

We proved the stock S650 suspension can survive big power, but 8-second consistency comes from controlling the IRS. The enemy is wheel hop, caused by the factory rubber cradle and differential bushings flexing under load and then snapping back.

Lock the rear cradle and differential down with billet lockouts and stiffer vertical links, using a kit like the BMR Bread and Butter II or the UPR Pro-Street package, and that wasted motion turns into forward bite and repeatable 60-foot times. It also protects the driveline from the violent shock of a hard launch.

A dedicated drag setup is free e.t. Skinny, lightweight fronts cut rotating mass and unload the nose, while a wide, light rear wheel makes it easier to plant the tire in the first sixty feet, which is where 8-second passes are won or lost.

We run Weld and Forgeline, and we also stock VMS, Race Star, and more. One heads-up: the larger Brembo brakes on Performance Pack and Dark Horse cars need 18-inch or larger fitments, so give us a shout if you need to confirm clearance before you order.

Tire choice is usually the last piece of an 8-second combination, and it is the one that decides whether all that power actually hits the ground. For a heavy, high-horsepower S650, a DOT drag radial like the Mickey Thompson ET Street R is the benchmark: huge bite off the line with far more manners than a full slick.

Size it to your wheel and how much sidewall you want, and remember these soft compounds wear fast and hate the rain. Our drag racing tire guide walks through the popular sizes and compounds so you can match the tire to your setup.