2029 Ford Mustang Mach-4Andrei Avarvarii - MotorTrendMustang looks, four-door practicalityAvailable V-8 and manualRear-wheel-drive performance potentialUnproven four-door dynamicsPotentially compromised trunk spaceProduction remains uncertainThe 2029 Ford Mustang Mach-4 would add two doors to the Mustang formula, making it Ford's first production four-door Mustang with an internal combustion powertrain. Like the Mustang Mach-E and Bronco Sport, it would expand the Mustang brand beyond its traditional form—but would it be as fun-first as the coupe?Likely rivals include the Dodge Charger, BMW M3, and Subaru WRX.What Is a Mustang Mach-4?The Mach-4 is expected to bring Mustang styling, rear-wheel-drive proportions, and performance-minded hardware to a more practical four-door body. Its mission sounds straightforward, but Ford will have to balance added space and convenience against the weight, packaging, and handling compromises that come with a longer body and two additional doors.Will the Mach-4 Use the S650 Chassis or Something New?It will likely use a stretched and modified version of the Mustang's existing S650 chassis, rather than an all-new platform. Ford could add rear-seat room and two doors at a lower cost by adapting the current rear-drive architecture, which itself evolved from the previous S550 platform. A clean-sheet chassis is still possible, but the cost-saving approach appears more likely.Which Engines Will Come in the Mach-4?It will likely borrow its core powertrains from the Mustang coupe: a roughly 315-hp 2.3-liter turbocharged four-cylinder paired with a 10-speed automatic, followed by an optional 5.0-liter V-8 producing around 480–500 hp.The V-8 could be offered with either the automatic or the Mustang's six-speed manual, giving the Mach-4 an unusual combination of four-door practicality and old-school enthusiast appeal (and the equipment to out-muscle-car Dodge).Ford could eventually add hybrid assistance, but current reporting suggests the initial lineup will focus on familiar Mustang hardware.A Four-Door Dark Horse?A four-door Dark Horse could borrow the coupe's 500-hp 5.0-liter Coyote V-8, available six-speed manual, Torsen limited-slip differential, MagneRide adaptive dampers, Brembo brakes, and more aggressive chassis tuning. Dark Horse–specific styling, wheels, tires, aero, and exhaust would further separate it from a regular Mach-4.Those components should be adaptable to the sedan, but not without changes. The Mach-4's longer, heavier body would require revised suspension tuning, added structural reinforcement, and potentially larger brakes and wider tires. Whether Ford would preserve the coupe's track focus or tune the four-door more to high-speed grand touring remains speculative.How Big Will It Be?The Mach-4 will almost certainly be longer than the Mustang coupe, with a stretched wheelbase and additional rear legroom to make its back seat genuinely usable. The current Mustang's rear quarters are best reserved for children or short trips, so simply adding two doors would not be enough; Ford would need to create meaningful space behind the front seats.Exact dimensions are unknown, but the Mach-4 should remain relatively low and wide rather than growing into a full-size sedan. Its fastback roofline could also compromise trunk space, particularly if Ford prioritizes rear-seat headroom and access. Expect a more practical cabin than the coupe, but not necessarily the expansive cargo area of a conventional family sedan.TechnologyThe Mach-4 should inherit the Mustang's current digital cockpit, including a 12.4-inch digital instrument cluster, 13.2-inch touchscreen, wireless Apple CarPlay and Android Auto, smartphone charging, and Ford's SYNC 4 software. An available Bang & Olufsen audio system and the latest Ford connectivity features would likely carry over, as well.Expect the usual suite of driver assistance features, including adaptive cruise control, lane centering, blind-spot monitoring, and automatic emergency braking. Ford could also offer hands-free BlueCruise, but it remains unclear how much of the Mustang's technology would be standard on the four-door model.When and How Much?If Ford's reported plans hold, the Mustang Mach-4 could arrive in showrooms in fall 2028 as a 2029 model. We think pricing will start at roughly $37,000 for the base four-cylinder model and about $50,000 for a V-8 version before destination and options. Both the timing and pricing remain speculative.