Mustang S550

The Ford Mustang S550 was Ford's Supercars car from 2019 to 2022 — the two-door coupe that replaced the FGX Falcon after Falcon production ended. It was succeeded by the Gen III Mustang S650 for 2023.

The Falcon's replacement

With the Falcon out of production from 2016, Ford needed a new body for its factory-backed program. The Gen II regulations — which for the first time allowed two-door bodies — let Ford homologate the Mustang, making the S550 the first two-door car in the modern championship, where four-door sedans had been the rule. Dick Johnson Racing (DJR Team Penske) led the homologation, with Tickford Racing as Ford's other lead team.

The Gen II control package

Mechanically the Mustang ran the established Gen II formula, shared with the rival ZB Commodore. Beneath the coupe body sat the common control chassis derived from the 2013 Car of the Future, a naturally aspirated 5.0-litre 90-degree V8 common to the marques, a control rear-mounted six-speed sequential transaxle and control differential, the Dunlop control tyre and E85 control fuel. As across the era, homologated dimensions and outputs were held to a control parity target and are not published here as precise figures.

A coupe body and the 2019 parity story

The notable change was the body itself: the S550 put a two-door coupe silhouette on the shared control chassis, a first for the modern main series after years of four-door Falcons and Commodores. Its aero (front splitter, undertray, rear wing) is a rules-controlled package best described qualitatively rather than in figures. The Mustang was widely reported to be quick out of the box in 2019, and the category moved to make mid-season aero adjustments after ruling the shape held an advantage — one of the defining parity episodes of the Gen II era. The specifics of those adjustments are not sourced here and are treated qualitatively.

Brakes, wheels and tyres

The tyre was the single-make Dunlop control. Brakes and wheels were not standardised in Gen II — make and specification varied by team, with several approved brake suppliers across the field; the single control-brake package only arrived with Gen III in 2023. Any single brake or wheel make quoted for the S550 reflects one team's fitment rather than a category standard.

Evolution

The S550 raced through 2022, its final year, before the Gen III Mustang S650 — on a new lower-downforce control chassis with a production-based engine — took over Ford's entry for 2023.

Sources: Gen II era control-formula catalogue rows (5.0L V8, control transaxle/differential, E85, Dunlop, Car-of-the-Future-derived control chassis) + the prior article — Grade D. No period official Gen II spec sheet or technical regulation was in hand; the 2019 aero-parity account is qualitative and unsourced here. Treat the technical rows as qualitative, control-target figures.