Brock 05 On-line Shop Champions

By November 1980, Commodore had been around for two years and the face lifted VC model (introduced in March 1980) was becoming almost as familiar as that of the old VB. There was still no question that, even in its various six-cylinder versions, this was the best Aussie family sedan on the market. There was a strong demand for the V8's and a 5.0-litre Commodore was generally a nicer device than a 5.8-litre Falcon.

But there was one problem. Point these two hotshot sedans down a straightish stretch of hot mix and Henry's was quicker - considerably quicker. This might have caused Queensland Falcon driver, Richard Johnson, some delight, but Holden driver, Peter Brock, would have preferred the opposite result.

So Brock decided to take matters into his own hands - here was not only a challenge, but also a sublime business opportunity. He would rework a top-spec 5.0-litre VC Commodore SL/E so it would out perform anything Henry built and also out handle and stop better than the General could make it do.

At this stage, the Special Vehicles operation, run by Brock in North Melbourne, was nothing near the size it is now. Peter Brock and his team were hardly in the car manufacturing business.

Outwardly, the original HDT Commodore - still commonly known as the Brock Commodore - might appear to be little more than a tastefully tricked-up SL/E with a fruiter exhaust note and fatter rubber. But it is better thought of as a whole new car game.

"There was strong demand for the V8s and a 5.0-litre Commodore was, generally a nicer device than a 5.8-litre Falcon.

Picture a truckload of VC SL/Es arriving at Brock's Special Vehicles operation. Each of these SL/Es is a 333 pack, which means it is equipped with the L31 5.0-litre V8 running through dual exhausts. On top of all the usual SL/E equipment there is central locking and fast glass. Venetian red, black or white were the colours

These cars disappear into the Special Vehicles workshop to have magic wrought upon them. This magic affects engine, suspension, braking and appearance, transforming the SL/E from a quickish luxmobile into a fully-fledged grand tourer - a combination, if you like, of Bathurst V8 supercar tradition and European finesse.

Perhaps the engine was the most difficult single aspect of the car for Brock to improve. Back in the easygoing 60s, there would have been no worries, but by 1980 there were Australian Design Rules to cover just about everything except ashtray design. Obviously Brock and his mates would have to drive their special Commodore through the exhaust-emission laboratory and convince the blokes in white coats that everything was legitimate.

While GM-H basically contributed little more than the Commodore itself to this process, they did not help Brock on the matter of ADR testing. They ran a prototype HDT through their Lang Lang emissions laboratory and it passed easily, further proof (should anyone require it) that a properly modded engine is not only more efficient but often no harsher on the environment than the standard unit.

The cylinder heads were machined for better gas flow. Larger inlet and exhaust valves replaced the standard ones. The inlet manifold was revised and assorted detail changes were made to tuning, not the least of which was fitment of a larger air cleaner and cold-air box. 
Brocks original HDT Commodore was indeed an impressive machine, both visually and against the clock
Old style twin exhaust mark this Brockie from the rest
There, amidst all the normal SL/E crushed velour and good gear, was a four-spoke, leather-bound Momo wheel replacing the standard one and - in the tradition of cars designed to be driven rather than merely motored - there was a footrest.
At the turn of the ignition key these changes manifested themselves in an unruffled 600-rpm idle. On the road, the Brock car not only felt quicker than the standard GM-H 5.0-litre Commodore but was smoother and much reviver. A bog standard 5.0-litre threatens to go into self-destruct mode at about 5200 and the useful maximum is probably about 4700. But the HDT Commodore's 308 would spin happily at about 5700.
Against the clock, the improvements were just as plain. The standing 400 metres time for the manual car dropped a full second from 16.4 to 15.4, with a similar improvement in the automatic Brockmobile - down from 17.4 to 14.4. And top speed? Running a 3.08 final drive, the manual 5.0-litre Commodore ran out of revs at around 190 km/h. Brock's beast however, could stretch its legs to 210 on the right patch of autobahn, while running the heavy-duty 3.36 slippery diff. Perhaps it wasn't quite as laid-back at a steady 100-km/h cruise as a standard 5.0-litre SL/E running the ultra-tall 2.6 gears, but when it came to getting places quickly…

At high speeds a standard 5.0-litre Commodore could feel a little unsteady. Peter Brock, long accustomed to coaxing various V8 Toranas down Conrod at upwards of 250 km/h, wanted to sharpen up the already good handling without sacrificing ride control. Like most enthusiasts he wanted to achieve a ride/handling compromise that in fact compromised neither.

Working in consultation with the Bilstein people in Melbourne, Brock devised a set of impressive modifications to the suspension. The Bilstein shocks themselves made plenty of difference, but the HDT Commodore also featured reworked spring rates as well as new roll centres, camber and castor. Beefier front and rear roll bars improved straight-line stability while sharpening turn-in and keeping the cornering attitude nice and flat.

At this stage in the plot we find handling and cosmetics coming together. Brock choose German alloy wheels from Irmscher Tuning for this car. These had the same offset but were an inch wider than the standard SL/E wheels. Tyres were fat Uniroyals. But it wouldn't have been the wheels and tyres that sized your attention first. No, one HDT Commodore's flairs and front and rear (boot lid) spoilers would have done that. Or maybe the stripes - brazenly emblazoned "HDT Commodore" - would have done the trick of stoping you in your tracks. This might have started out as a Commodore, but just look how it finished up. Here is the car that took up the body kit trend started by the A9X Torana and turned it into a craze.

Modesty and the HDT Commodore didn't really belong together, but a surprising number of owners asked for their cars to be delivered minus the striping.

The man behind the facelift was the then boss of GM-H styling, silver-haired, silver tongued and ever so extroverted Leo Pruneau. Back in 1983, Preneau was winding up his stint at Fishermen's Bend and spoke openly about his involvement with the original HDT Commodore.

"Peter wanted what he called a 'ballsy' car with as much distinctive exterior appearance as he could manage. He wanted the biggest wheels and tyres he could possibly fit under the sheet metal, but wanted the interior to be as refined as possible. We wound up with a luxury hot rod and I'm not sure those two elements are compatible. The flairs and tail were okay, but the big problem was the stripes, which were often deleted.

I probably prefer the car without the stripes myself, but think the white cars are by far, the best looking of the lot. If we'd had a black interior we'd have used the bright red (Flamenco Red), but I didn't like the bright colour combined with the red interior. "

The Brock imprint found its way into the cabin as well. There, amidst all the normal SL/E crushed velour and good gear, was a four-spoke, leather-bound Momo wheel replacing the standard one and - in the tradition of cars designed to be driven rather than merely motored - there was a footrest. (Why it took GM-H a further five years to get around to installing such an item in all Commodores is anyone's guess; ask the beam counters).

Peter Brock was wonderfully thorough in his approach to improving the Commodore, even the brakes earned attention. A larger capacity master cylinder was installed mainly because this item had proven its worth in the Repco cars of 1979, another sign that racing/rallying really does improve the breed!

Looking back on the original Brock Commodore from the lofty heights of 1987, it is impossible not to be mightily impressed with what that car represented in 1980. Simply, it was the first of a new breed of Aussie supercars. It had similar performance to the Monaro GTS 350s and many of the Falcon GTs (no, not the Phase III, we admit), but it also had a certain classiness about it that the earlier road rockets had never achieved. If the brilliance of the Holden Commodore itself always had to do with its blending of European and Australian design, then that combination truly shone in the HDT Commodore. Perhaps that's why so many were ordered without the stripes -

so that all those young doctors and advertising executives could choose a Holden Commodore V8 instead of a BMW, and park it in the official car park without too much ridicule from their peers! No wonder the first HDT production vehicle is already a blue-ribbon collector car!

"Looking back on the original Commodore it is impossible not to be mightily impressed with what that car represented in 1980."

Commodore Crazy - 1987
Article reproduced courtesy of Sean Walker -Commodore Crazy - FPC Magazines.
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