This must almost go on record as the quickest concept of its type to go from idea to reality. Peter Brock's latest road car, the Group Three Commodore, was only proposed as recently as Easter this year. At a gathering of the faithful on the Calder raceway not three months back, the HDT succumbed to pressure suggesting the time was ripe - what with all the controversy over the current Group A - for a Group Three Commodore comeback.

It's far from being a secret that Brock was never happy with the unleaded, red VL. Even cars fitted with the well-known "Plus Pack" didn't have the punch a full-blown HDT road car should have had.

The Group Three is intended to revive tradition. Lake the last, thundering HDT car with that name, the new version is available only in white. Like that car, it also has locally made ROH road wheels - of basically the same design as those fitted back in 1985.

It also has a powerhouse of an engine, claimed by HDT people to produce as many back wheel kilowatts as the current Group A does on the engine dynamometer. There's no real secret to this - apart from a certain amount of blueprinting and cunning bit of work on the exhaust system, which Brock says, meets ADR emission requirements.

Basically, what the HDT has done is bypass the catalytic converter at high levels of exhaust manifold pressure via a standard EGR valve and length of piping welded onto the exhaust. "At full throttle the engine generates sufficient combustion heat to make the converter unnecessary" says Brock. Combined with a high compression ratio (9.3:1) big valve head with machined and matched ports, blueprinted carburettor and distributor, and a heat shielded, accurately metered fuel system, this gives the Holden V8 sufficient verve to top a few substantial chucks off the car's acceleration times. Testing with an automatic car, Brock's people have recorded 400 metre times in the low 14's, a full second better than a sweet running VL Group A.

At the time we went to press, the HDT was still tweaking the engine, but the claimed figure - bearing in mind different dyno techniques used by HDT and Holden - was around 190 kW, which is a substantial improvement over the VL Group A's 137 kW.

Significantly, every Group Three produced by Brock will have its engine dynamometer checked (the HDT is about to install its own unit) and will be fully emissions certified.

At first somewhat surprising, but on reflection a bit less so, is the decision to adopt the three speed Borg Warner automatic as standard transmission for the Group Three. Brock says the idea with this is to produce a "subdued, M series BMW style vehicle with an element of conservatism". The auto box fits in well with this concept - and it obviously performs well, as acceleration times indicate. It also fits in well with the fact that Brock now has to build the cars without cooperation of Holden's. For those must have it, the imported Borg Warner M5 is available as an extra cost option.

Suspension of the Group Three is the same as that fitted to HDT "Plus Pack" Group A's - including re-rated springs, shocks and, with the energy polarizer that is of course fitted, lower recommended tyre pressures.

Presentation of the VL Group Three, with the all white paint, is clearly reminiscent of the VK version of 1984, although the cosmetics are very much a development of the Group A.

The car is based mainly on the Berlina model, but it does get a Calais nose and an extensively re trimmed interior. About $17, 000 is put into the car, according to Brock.

The front spoiler is a much cleaned-up affair with mesh protectors on the intakes, there's a modified, lower-profile boot spoiler, and an intergraded side skirt similar to that seen on the LE Calais. The rear bumper also incorporates a skirt attachment, which provides an outlet for the single, big bore exhaust. Wheels are machined, altered offset 16 inch version of the ROH units fitted to the last Group Three, with the radial fins milled back purely for aesthetics rather than function. They are attractive nonetheless and significantly cheaper than imported wheels. Tyres are 225/50 uni-directional Bridgestone RE71s.

The interior has received a lot of attention from Brock. The aim has been to eliminate entirely any sign of vinyl covering and apart from one small strip on the doors, it has been successful. Two choices of front seat will be available - either an Australian made, Brock designed front bucket with enough shaping to hold one securely (but not too much access be difficult) or the familiar Scheel unit.

The claim is that the interior will be trimmed to a higher standard than Calais. Only three options will be available - manual gearbox, air conditioning, and HDT installed sunroof, which Brock says will be priced very competitively.

Price target for the Group Three is $40,000.00 - a figure not yet finalized as the HDT puts its finishing touches to the interior. The aim is to build around 40 cars per month until the end of the VL life.

It would be difficult for Brock to look more assured than he does that the HDT will be still operating by that time.

Car Australia July 1987 Edition.

Peter Brock's view of the HDT's role is different to the way he may have seen it in the days when he was approaching second manufacturer status in Australia. Brock isn't often asked, and doesn't really volunteer to talk about the polarizer, or Holden's these days. About the closest he came to the issue in our recent discussion was to say that the situation with Holden's now allows HDT more freedom is sourcing its components.

Although he is still obviously a Holden oriented man, he sees the present situation as being something of a release for his company. "We have been able to build the new Group Three without constraints. We're never been satisfied with "near enough" engines. Where the volume produced factory engines have to compromise, we are able to optimise. With the fuel system, for example, we are able to achieve accurate metering to two psi where a normal Holden V8 will vary at anything up to four psi."

Brock today is also getting into the dealer fitment area with what he calls his new "designer Series" range of cosmetic bolt-ons. "What is actually happening here is that legitimate HDT components are now available to the accessory market. Previously you just had copies, or other alternatives that often weren't as good.

So exit Peter Brock, second manufacturer, and enter Peter Brock industry supplier …