WHEN it comes to building a quick street car, there is more than one way to skin a cat these days. As Steve MacGregor will attest, sticking with a naturally aspirated Holden V8 is by no means the easiest or most economical approach, but when your weapon of choice is a cool-as-hell, period-styled HZ Premier, keeping it pure of heart is an all-important consideration.
As the proprietor of Warragul Exhaust Centre, Steve is in the business of getting tough street cars to make the right kind of noise, and he reckons there are few sweeter sounds on this earth than a well-warmed, high-compression plastic motor spinning past 8000rpm. We reckon he’s right.
“Us Holden V8 guys are a dying breed!” Steve admits. “All the cool kids run turbo LS engines these days and they’ve left us in the weeds, but I’ve loved my Holdens since day one, and you just can’t beat the sound they make.”
This is the second Atlantis Blue HZ Steve has owned. The first was left to him by his father, but as often happens, he was forced to part with it in order to buy his first home. Twenty-five years on, he still hadn’t beaten the urge to build an HZ that was just like his old one, only faster. He went in search of the perfect base vehicle for his project and tracked down this example in Hillside, Victoria.
“The car was a standard 253/Trimatic car when I bought it,” Steve says. “I drove it around like that for a while; then Johnny Pilla from Powerhouse Engines built me a motor. I wanted to run a 10-second pass.”
Johnny specced a 383ci combo with a COME crank, Callies Compstar rods and forged JE slugs, with a Comp solid-roller cam, CNC-ported VN-style cast-iron heads and 12.1:1 compression. An 830cfm Pro Systems carb sits atop a COME single-plane manifold, and the headers and exhaust system were custom-made by Steve.
“I went over the top because I’m an exhaust guy – there were 110 hours in the headers alone!” he says. “They are four-into-ones, with a twin three-inch system running twin hotdogs and Di Filippo mufflers. When I get to the track, the whole system can be unbolted in about a minute.”
The engine is good for 576hp on BP Ultimate and 604hp on E85, but Steve has found E85 blends to be inconsistent, so as a bracket racer he has stuck with 98-octane pump gas in the interest of repeatability. With the new engine combo bolted in, Steve took the Prem to the track and went hunting for a 10.
“The fastest car I’d raced at that point went 13.9; I did two passes in it and that was the extent of my drag racing experience!” he says. “Johnny from Powerhouse came to Heathcote with me, and the car went 11.66@118mph on its first pass. By the end of the day we got it down to an 11.35@125mph, then we pulled the converter out, sent it to TCE and had it increased from 5500 to 6200rpm. Next time out the car went 11.1 straight off the trailer. Then we were stuck there for a while, with the next dozen or so passes all within a couple of tenths; all I wanted to do was a 10.99!”
Steve made it his mission to learn about suspension set up in the hope of reducing his 60-foot times, and his research led to him installing a set of Pedders 90/10s and standard HZ six-cylinder springs up front, as well as LH Torana coils, Koni adjustables and a swaybar in the rear. “As soon as we got that stuff right it went straight into the 10s, so I got the car tech-inspected and then pulled it apart for a full rotisserie restoration.”
Steve entrusted Drouin Smash Repairs with the paint and panel work, and aside from the deletion of the side moulds and wheelarch moulds, everything is to factory specs, including the Atlantis Blue paint. Likewise, the interior was done in original-style Buckskin vinyl by Dave at Warragul Auto Interiors. Only the B&M shifter, Auto Meter instruments and bolt-in, ANDRA-spec half ’cage differentiate it from standard, but Steve does fit a Kirkey race seat for track duties.
Because the car had been built, driven and raced before it was pulled apart, reassembly was a walk in the park. “It went back together almost like a kit,” Steve says. “It was actually really fun; all the pain had been taken out of it.”
In April last year Adam at ATS Automatics in Bendigo treated the Turbo 400 to a freshen-up, and the car went 10.91@123mph in tough conditions at the inaugural Red CentreNATS in September. Two weeks later at Calder Park it went 10.68@128mph. “I’m rapt with how far it’s gone into the 10s,” Steve says. “My dream was to run a 10.99, so when it went 10.68 I was tooting the horn and banging on the dashboard and giving the old girl a bit of a pat! It’s done a best of 1.53sec to the 60-foot mark, and now it runs 10.7s all day in the heat at 3500lb.
“I love the attitude of an angry aspirated car and it gets driven on the street a lot,” he continues. “When you tell people it has a 6200rpm converter they look at you like you’re an idiot, but the converter is really tight and the car is extremely driveable. It doesn’t get hot even on 34-degree days, and the block is half full of concrete!”
Consistent mid-10s at full weight on pump fuel and radial tyres proves that there’s life left in Holden’s homegrown bent-eight yet, and the occasional show ’n’ shine trophy illustrates just how well-rounded Steve’s Prem is. He tells us he’s keen to put together a plastic-powered entry for Street Machine Drag Challenge, and we can’t wait to see what he comes up with!