Dave Bennett is one of the great success stories of the Australian high-performance automotive industry. ‘Dyno’ Dave has now put finger to keyboard and produced an autobiography, Dyno Dave: The Yella Terra Story. This is an edited extract, focusing on two

In July 1967 we transitioned from being a sole trader to a registered company and the business became Perfectune Automotive Services Pty Ltd and I became Managing Director and my wife Jan Secretary-Director. In the same month I took delivery of one of the first HR 186S four-speed Holden Premier sedans. It featured Silver Mink paint with a black vinyl top and the all-black interior featured front bucket seats.

This model is recognised as being Holden’s first real attempt at producing a performance car, at a staggeringly low $3165 compared to the Falcon GT at $3890. Standard mechanical equipment included a steel crankshaft in a High Performance block plus a special camshaft, a dual throat carburettor, cast iron exhaust headers with a split exhaust system into one pipe, front power boosted disc brakes, a floor shift for the four-speed gearbox and a 3.55:1 ratio limited-slip rear-end.

We immediately set about modifying the vehicle with a stage two modified cylinder head, a tachometer mounted in the centre of the dash, a wood rimmed steering wheel, lowered suspension, heavy duty shock absorbers and a heavier front sway bar, plus mag wheels, radial ply tyres, a blacked out grille and a red stripe down each side.

I had discussed the idea of selling clones through the local Holden dealer, Mentone Motors, who had supplied our car. I was friendly with the Dealer Principal Jim Faulds and his two drag racing sons, Bill and Daryl. The idea seemed like a good fit.

This concept was way before Holden Special Vehicles (HSV), Brock Commodores and 21 years before the VL Walkinshaw Commodores appeared on the market.

We called the converted car the ‘Perfectune Sprint GT’.

It was tested by several magazines and the Motoring Editor of the Melbourne Sun newspaper Peter Costigan. It received excellent reviews. Respected motoring journalist Peter Robinson reported in the Australian Motor Sports magazine that it was the best Holden he had ever driven. He reported that it was quicker to 100mph (162km/h) than the Ford 289ci GT XR Falcon.

This was quite remarkable considering that this was a six-cylinder car compared to a V8, certainly helped by the low 3.55:1 diff ratio, compared to the high 2.93:1 of the Falcon that was 17 percent heavier.

However the GT Falcon, by virtue of a V8 engine with 55 percent more cylinder capacity was certainly faster overall with a top speed some 10 mph higher.

Herein lies a mystery. Some 48 years after the magazine was published I asked Peter Robinson about his reporting that the car was quicker to 100mph than the Ford. He said that was impossible and his statement was incorrect, just a bit late to retract!

GM-H had certainly taken notice of all the publicity. Sales Manager John Bagshaw, (later Managing Director) entertained me, discussing possibilities for some time in his huge oak-lined office at their Fishermans Bend headquarters. Meanwhile GM-H’s manager in charge of motorsport Peter Lewis-Williams ran a few tests on the Fishermans Bend airstrip that was nearby to the Holden head office and plant.

The very big wheels at Holden must have turned exceedingly slowly. It seemed an age before they subsequently ordered one of the stage two heads for testing purposes at a cost of $130. The outcome of this entire exercise, I will mention later.

Sadly the idea came to nothing, almost certainly because the HK Monaro range which included the first Holden equipped with a V8, a 327ci Chevrolet engine, was well and truly in the pipeline.

A year prior, we were unaware of this impending and dramatic expansion of the Holden range. When I was told of the new models, I ordered a GTS 327 ‘Bathurst’ Monaro for delivery in August ’68.

I sold the HR in March ’68 to a dealer who sold it next day to Wally Hook, an employee of a local printing company not far from our workshop. He changed the registration from the original JUS-723 to HR 368 (representing the third month of 1968). We continued to service it for some 16 years, but eventually lost contact with Wally, as in 1989 we closed our service department to concentrate on manufacturing.

Advance to 1998 now, some thirty years after I had sold the HR, and the car’s only other owner Wally Hook drove up our driveway and parked the car outside our offices. Through my window the car looked just as I remembered it all those years before. Wally came into reception and I met him. He was pleased I remembered him; how could I forget? He asked me if I knew anyone who would be interested in buying the old girl, which he had for 31 years. He said, “I am now 80 and my eyesight is failing and my wife does most of the driving in her car.”

After a walk around inspection I had quick drive for old time’s sake. I gave it a pretty good workout, around what was our old test track in local streets. It was a delight, slipping through the gears in the four speed box with the nice floormounted stick. I was hooked…this just had to be! I bought it back from Wally, who had been the ‘custodian’ for all those years.

The car had always been garaged, the body and interior was in very original condition and it had done 114,000 miles (185,000km). Once again I was owner of the car, complete with the original selling dealer’s booklet that contained my name and old address and stack of receipts. In effect it is a two-owner car that I still have to this day. Its 50th anniversary was in July 2017.

As a marketing tool, over time we exhibited it the Canberra ‘Summernats’ and Federation Square in Melbourne, quite apart from many club runs and display days. We put together an historical display panel which we place in front of the car which we still use at the time of writing.

Upon reflection, it is obvious that the HR Sprint GT was very much the catalyst for the long-term commercial relationship that, within a few years, developed between Perfectune and Holden.

The Monaro phase

On Friday, August 2, 1968 I took delivery of a Warwick Yellow HK GTS 327 ‘Bathurst’ Monaro, one of the first delivered in the country. What an absolute fireball it was!

Without bothering with the traditional formalities of ‘running in’ the engine, I immediately ‘ran its ring off’ on the dyno, and then set off to drive it to Mt Gambier and back. I called on a few customers on the way to Warrnambool and after leaving Portland, I headed for Mt Gambier passing a few cars and then cruising at around 100mph (162 km/h).

I was unloading things at the motel when a Holden pulled up beside me and the driver said, “You really must know somebody to have a Monaro only a few days after release.” He was the Holden Zone Service Manager and said he had followed me but there was no way he could catch me!

On return we ran it on the dyno quite a lot and the following weekend on Sunday August 11, hauled it to Calder. On the stock Dunlop Red Streak tyres with the mufflers off and 100psi in the front tyres, it ran 14.46 off the trailer and became the first Monaro on a drag strip and quite likely the first ever raced.

Although I was a committed drag racer, I was also keen to stay involved in other motorsports. I decided we should have a go at the production touring car race at Sandown Park in September, 1968. Through our motorsport connections I was introduced to a potential co-driver, Henk Woelders, an experienced ‘open-wheel’ racecar driver who had BP sponsorship that meant we were provided with free fuel and lubricants.

My friend Ray Misson, who had worked under me at Boyanton Motors, was now with Holden distributor, Preston Motors in Dandenong. Ray looked after our normal parts requirements and he arranged for a good range of spares to be on hand for practice and race day, so we had Preston Motors signage on the car.

During Saturday practice, Henk was clearly the quickest, qualifying on pole position, the best place to start any race. The car’s clearly superior performance requires a little explanation and the answer is relatively simple.

The other Monaro drivers were revving their engines out to 5500rpm in the indirect gears because that’s where the tachometer was redlined. Remember these were really stock standard passenger cars, not specially prepared and developed race engines. At this speed the engine would be what I call, ‘running out of puff’ which we had determined with our dyno testing.

Our secret was a little English made device called a ‘Bomonk Dynometer’, a combination decelerometer/accelerometer or ‘G’ meter. It was mounted on the floor of a car for brake testing, while for acceleration measurement it attached to the windscreen with a suction cup. I had proven its benefit in drag racing and when testing modified road cars. These days you can get a

mobile phone app that does a far better job!

When the car accelerated, a needle on the dial rose. When it stopped accelerating the needle started dropping, indicating the point to change to the next higher gear. As a result we never took ours past 3750rpm, which we proved on the dyno was right on the top of the torque curve. This basically explains the superior performance of an otherwise identical car.

With the car on pole and Henk driving, the race started. Immediately the car showed its superior performance, quickly pulling away from the rest of the eld at almost a second a lap quicker than the second-placed car.

By the 11th lap he was leading the race by nine seconds, well ahead of the Porsches and other Monaros. He had just ashed by the main grandstand when suddenly the car suffered a total loss of braking and speared off the end of the main straight at about 130mph, (210 km/h) in spectacular style. It jumped the Armco railing and landed almost on the roadway beyond.

I was standing at the pit wall fairly close by and saw the whole catastrophe. I immediately thought, ‘Wow, that’s just like the crashes at the Daytona Super Speedway in the States.”

The brake failure was caused by one of the right rear brake linings separating from the brake shoe, resulting in complete brake failure despite the so called ‘dual master cylinder’ brake system. This was introduced with the HK range, obviously not designed to handle such a catastrophic failure. Prepared by a brake specialist, the high quality linings were only ‘bonded’ with an adhesive to the shoes, which was a normal practice for road cars. If they had been riveted as well, the failure almost certainly would have not occurred.

On re ection, this was an oversight by all concerned, myself included. The race was won by another GTS 327 Monaro driven by Holden engineers Bob Watson and Tony Roberts. I guess they knew a lot more about the model than we ever did. Even so, they nished the race with virtually no brakes for the last few laps.

A rumour surfaced that our car performed so well because the engine had been modi ed in some way, making it illegal. The truth is that not even the rocker covers had ever been off the engine since new, and it was absolutely legal.

We won $3 for each lap we led, a total of $33.00, but it cost about $1000 to repair the surprisingly little front end damage.

The following morning I had a phone call from a person who told my office staff he was the Managing Director of General Motors Australia. He said in an American voice, “Mr Bennett, this is Harlow Gage from General Motors. We want to congratulate you on showing the public of Australia what a ne motor vehicle the Holden Monaro is and furthermore what a brilliant steeple chase vehicle it is too.” He then hung up!

More touring car racing

Idecided to have another shot at production touring car racing. Very few modi cations were permitted. A lot depended on preparation, tyres and especially driving skill. However, my foray was short lived.

To increase power I removed the heater from the rewall and connected a large convoluted exible hose from the rewall to the air-cleaner. At speed this fed high pressure air from the base of the windscreen to the engine, in effect a form of supercharging, giving a tremendous power boost. The faster the vehicle went, the greater the boost.

At Phillip Island, in practice I took six seconds off the lap record, I remember going at out down the main straight towards the sweeping right hand KLG Corner and thinking to myself, ‘This is just like ying in a car.’ Honestly, it was a bit scary.

A few laps into the rst race, the engine, that still hadn’t had the rocker covers off, blew up in a very big way, after a piston failed. The conrod wrecked the block, smashed the cam into seven pieces and badly damaged the sump. The car spun dramatically when oil instantly reached the rear tyres.

This incident occurred just before Repco Corner, by co-incidence almost exactly where Murray Carter ipped and wrecked the original Corvette monoposto open-wheel racing car 10 years earlier.

I made the decision that circuit racing wasn’t for me, and decided to pursue hillclimbs and drag racing. For far better reliability, I sourced a 327 Chevrolet Corvette short motor with strong forged pistons, conrods and a factory high-performance camshaft matched to a pair of now redundant exNorm Beechey Chev heads that were originally ported by Perfectune.

This enabled us to get the car back in action very quickly.

With this combination and higher than the standard 9.0:1 compression ratio (now 11.5:1) and using 115 octane aviation gasoline, the car really ew.

I ran the Monaro at the now long defunct Templestowe Hillclimb. With the car in basic drag racing trim, except for wheels and tyres, I set a new record of 56.1 seconds for Touring Cars over three litres on my rst scorching run. This was 3.5 seconds quicker than the previous record set by Peter Lewis-Williams in a Ford XR GT 289. This record was never broken and the hillclimb closed in 1970.

Another defunct hillclimb track was Lakeland, run by Jim Abbott on his private property in the Dandenong Ranges. I set a new record at this track, however I am unsure that was ever broken before it also closed.

All the while I was getting deeper and deeper into drag racing, hauling to interstate race meetings. A few employees generally came out to the track if I ran in Melbourne. It was all part of what racers refer to as “racing on a shoestring”, something of which I am proud.

I have never understood the need for all the crew members that some competitors have. I’m a bit of a loner at times and I like to do things my way. I do regret that we didn’t have Yella Terra products in those days, because the car, although extremely good for publicity, would have been fantastic for our later products.

The Monaro was a great favourite with fans and track managements and was matched with everything from a V8-powered motorcycle to a Top Fuel dragster.

I go into detail about the Monaro’s quarter mile career in the actual book, but for this extract I better wrap things up on the topic.

My accountant was tipping that 1970 was going to be a pretty tough year for the business. I decided to sell the Monaro and concentrate on business.

I bought a new ve-litre Monaro engine, tted it up to the Saginaw gearbox, put the car back otherwise to standard and changed the 327 front guard badges to ve-litre ones.

I sold it to Kevin Dennis Motors in Preston. Lord knows where it is now, probably melted down into paper clips. I’d love to have it back. If anyone reads this and knows of a Monaro with the Bathurst long range tank and a Saginaw gearbox with some unusual holes adjacent to the gearbox cross member, where we bolted the traction bars, then I’d love to hear of it. It was with great regret that I sold the car.

I sold the engine and the very low ratio, 4.88:1 rear axle assembly to Daryl and Bill Faulds who incorporated these into a HB Torana Funny car they called the ‘Perfectune Head Hunter’. Originally it was named ‘Thee TORANA’.

Having effectively quit competition activities, I really concentrated on expanding the growing business which required more ideas and the ploughing back of pro ts into more machinery and vehicle servicing equipment. But the bene ts of the promotional value of all of the Monaro competition activities as well as show appearances cannot be underestimated. The ow-on effect on business lasted for many years.