13/08/2026
I’d like the PRV to have just as a cool a story but …. It ain’t
In 1981, Austin Rover had a problem. Every other manufacturer entering Group B rally racing was building turbocharged four-cylinder monsters: the Audi Quattro, the Lancia Delta S4, the Peugeot 205 T16. Turbocharging made sense on paper: more power from less displacement. But turbo lag in 1980s technology was measured in seconds, not milliseconds. On a narrow forest road at 100 mph, the difference between pressing the throttle and receiving power could mean the difference between making a corner and hitting a tree. Austin Rover's motorsport director, John Davenport, made the contrarian call: no turbo. A large-displacement naturally aspirated engine with instant throttle response. They hired Williams Grand Prix Engineering — the Formula 1 team — to build the car. Patrick Head designed the chassis. Ex-Cosworth engineer David Wood designed the engine. The base vehicle was an MG Metro, a shopping car smaller than a Honda Civic. They put the engine behind the driver.
The prototype used a temporary engine created by cutting two cylinders off a 3.5-liter Rover V8 — the same all-aluminum Buick 215 V8 that GM had sold to Rover in 1967 and that had won two Formula 1 championships as the Repco-Brabham. With two cylinders removed, the Rover V8 became a 90-degree V6 that proved the concept while David Wood finished the proper engine. The production V64V (V6, 4 Valves per cylinder) shared some architectural DNA with the Cosworth DFV but was a clean-sheet design: 3.0 liters, bore 92mm, stroke 75mm, all-aluminum block and heads, quad overhead cams, 24 valves, Lucas electronic fuel injection, dry-sump lubrication. The International specification made 410 HP at 9,000 RPM from 183 cubic inches naturally aspirated. That's 2.24 HP per cubic inch. Without a turbocharger. Zero-to-sixty in 2.5 seconds. The same specific output as the Ford FR9 NASCAR engine — from a rally car engine designed by a Formula 1 team and based partly on a Buick V8.
Group B was banned after the 1986 season following a series of fatal crashes that convinced the FIA the cars had become too fast for public roads. The Metro 6R4's competitive career lasted barely one full season. Tony Pond finished third at the RAC Rally in 1985 behind two Lancia Delta S4s. The 6R4 never had the development time it needed. But the V64V engine refused to die. Austin Rover sold the engine design to Tom Walkinshaw Racing (TWR), who bored it to 3.5 liters, added twin turbochargers, and installed it in the Jaguar XJR-10 and XJR-11 Group C sports prototypes. Output: over 700 HP. Those Jaguars raced at Daytona and Sebring in the IMSA GTP championship — the same American tracks where Corvettes, Porsches, and Nissan prototypes battled for endurance racing supremacy. A rally engine from a British shopping car, turbocharged by a Scottish racing team, racing under a Jaguar badge on American soil.
