W427

WHEN Holden Special Vehicles planned the celebrations for its 20th anniversary, it decided it had to produce a very special car to commemorate the event, and the result is the limited-edition W427.

The name, however, honours the company’s founder – Scotsman Tom Walkinshaw – and the engine capacity in cubic inches, which translates to 7.0 litres for those of us in the metric world.

Production has been capped at 427 units, but there is no guarantee that HSV will build this many because they say it depends on demand. In any case, it will take quite some time to build 427 cars because they are being hand-built at a rate of only a handful per week.

The LS7 engine was developed for the Chevrolet Corvette in the United States and comes almost complete from General Motors in Detroit, but HSV adds its own dry sump, exhaust system and cold air induction system at Clayton. The car develops a heady 375kW of power at 6500rpm and 640Nm of torque at 5000rpm.

That required considerable internal upgrades to the Tremec TR6060 six-speed manual gearbox as well as the cooling system, limited slip differential, clutch, wheel bearings and brakes (which have six-piston front calipers with 50 per cent more pad area than the HSV GTS and two-piece 380x35mm floating rotors rather than 365x32mm single-piece rotors).

The W427 rides 20mm lower than HSV’s previous flagship, the GTS on which it is based, the springs are 50 per cent stiffer and the rear suspension bushes are stiffer.

Externally, the subtle differences include a slightly different nose, a three-piece carbon fibre rear spoiler and new 20-inch alloy wheels.