Roush Performance just cleared the last hurdle for its 2026 Ford Mustang supercharger kit, announcing E.O. approval under E.O. D-488-72 — making the system 50-state legal, including California. The kit pushes the 5.0L Coyote to 810 horsepower and 630 lb-ft of torque, numbers that sit squarely in Shelby GT500 territory. The kicker: it fits under the factory hood and K-brace without a single cut, drill, or body modification. An Inverted Eaton TVS R2650 Is the Key to Making It All Fit Roush PerformanceThe engineering centerpiece is an inverted Eaton TVS R2650 supercharger developed in partnership with Magnuson Superchargers. Roush oriented it with a front-inlet, front-drive layout — a deliberate packaging choice that keeps the blower's profile low enough to clear the factory hood line and K-brace without any sheetmetal surgery. That's not a small achievement on the taller S650 engine bay architecture.Peak boost comes in at 13 psi at 7,500 rpm. Rather than swapping in a single large throttle body — the common shortcut on aftermarket kits — Roush retained the factory dual 80mm throttle bodies. The dual setup delivers more total inlet area than most single-throttle competitors, which Roush says translates directly to improved throttle response and driveability, not just peak horsepower. The result looks factory-correct from the top of the engine bay, which matters to the clean-build crowd this kit is aimed at. Cooling, Fuel, and the Hardware That Keeps 810 HP Honest Roush PerformanceMaking big boost reliable under sustained load required more than just bolting on a blower. The cooling package pairs high-efficiency twin intercoolers with a large front-mounted heat exchanger and a high-flow Bosch PCE intercooler pump — a combination engineered to pull intake air temperatures down and keep them there during back-to-back runs, not just on a single dyno pull.The fuel system got a full upgrade to match. High-flow dual-cone fuel injectors, optimized director plates, and CNC-machined billet fuel rails handle delivery with the precision the power level demands. Roush also added a custom Front End Accessory Drive system to reduce crankshaft load, optimized the supercharger belt path, and spec'd colder-range Ford Performance spark plugs with a reduced gap for safe combustion at elevated boost. Plug-and-play wiring means no splicing, and calibration is handled through Roush Diagnostic Tool software — an OEM-level flash process that keeps diagnostic capability intact.That combination — serious forced-induction output, OEM-level fit, and nationwide legality — is exactly what S650 builders have been waiting for. At $10,399 with a 3-year/36,000-mile limited powertrain warranty, Roush is positioning this as the clean-build answer to big power on the 2026 Mustang GT and Dark Horse. GT500 Power, Stock Bay, 50-State Legal — What This Means for S650 Builders Roush PerformanceThe Shelby GT500 made 760 horsepower from its supercharged 5.2L Predator V8 — a purpose-built engine that Ford no longer offers in the current S650 generation. Roush's kit extracts 810 hp from the 5.0L Coyote that's actually in showrooms right now, with a warranty behind it and a CARB exemption order that lets owners register and drive the car in all 50 states without emissions worries.For Dark Horse owners especially, this is a compelling path. The Dark Horse already brings upgraded cooling, a higher-revving Coyote tune, and track-focused chassis hardware to the table. Drop in this supercharger kit and the gap between a street-legal S650 and a GT500 — a car Ford no longer builds — closes fast. The $10,399 price includes all installation hardware, and the kit is available now through RoushPerformance.com.Gearheads who've been holding out for a clean, warranty-backed, street-legal forced-induction solution for the S650 finally have their answer. Roush built this one to look like it came from the factory — and hit harder than anything Ford currently sells with a Mustang badge.
