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540-cube big-block 1977 Holden HZ one-tonner

By John Bennis | Photos: Ellen Dewar, 07 May 2018 Features

540-cube big-block 1977 Holden HZ one-tonner

Andy Fensom's Tonner put him through hell, but it's now an immaculate conception

This article on Andy's Holden one-tonner was originally published in the April 2018 issue of Street Machine

ANDY Fensom has a thing for Holden one-tonners; this is the second one he’s owned. “I’ve always liked the shape of them,” he says. “I had to up the ante the second time around, though; the last one-tonner I had was just a bit of a burnout ute, so I wanted to take this one to the next level.”

Holden One-Tonner topviewAndy bought the car in 2010 from Brisbane as an unfinished project, and, like so many unfinished projects, it didn’t come with all of the original parts. “I got nothing when I bought it,” he says. “I had to find all of the parts, from window moulds to door handles. It turned out to be much more difficult than I first thought.”

The tonner wasn’t much to look at, but it was always going to be a big project. “It came with flat paint, a rollcage, a nine-inch housing under the rear and that’s it,”

Related: Grand champion-winning procharged Holden HQ one-tonner

Holden HZ one-tonner rearWheels were an important piece of the puzzle for Andy, and you can’t go wrong with a set of Center Line Revs. The fronts measure 15x4, while the rears sit at a fat 15x10 clad in 275-wide Mickey Thompson tyres

Andy says. “Somebody had started the project, but for whatever reason they didn’t have the money or time to finish it. The finished product took me and my mates four years of hard work in a tiny garage. The only tools we used were ones we could buy from Bunnings.”

Related: Twin-turbo 1974 Holden HJ one-tonner

Holden HZ one-tonner sideLow and mean – that’s this ute in a nutshell. Personal touches, such as the scoop running the length of the bonnet and the custom tray, really give Andy’s tonner an imposing presence – especially from the side

Andy was set on having a ute that he could enter in shows, burnout comps and even sound system competitions, which is why he put quite a serious stereo in it. “I wanted a car I could do anything I chose to do with it,” he says, “and I wanted it to be fully engineered and street-legal.”

The custom tray was built by Andy with the help of a mate. It took three months and eight sheets of 1.5mm steel to get it perfect, all cut with a four-inch grinder. “The tray ended up weighing around 200kg,” he says. “My painter hated it because it was so hard to move around. He tells me he needed a massage after he finished buffing it because he had to reach so far!”

Holden HZ One-TonnerWith the tray and bodywork sorted, the ute was painted, and then a new interior was fitted up, swathed in leather trim from the door cards to the roof. Andy designed the dash cluster himself, going for a custom look. “The upholsterers did an amazing job of completing the trim while working around the rollcage; I wanted the ’cage barely visible,” he says. “Even with the dash, there’s no visible screws. All up it took around 160 hours to complete, they tell me.”

Andy’s good mate Lindsay completely rewired the car from scratch. Andy wanted most of the switchgear to live in the centre console, while his desire for push-button start meant getting rid of the key barrel.

Related: 454-cube big-block Holden HQ one-tonner

Holden HZ one-tonner exhaust“Everything in terms of the interior was smooth sailing until we tried to fit the rear windscreen,” Andy says. “Whoever welded up the flat wall at the rear – someone to do with the previous owner – did it wrong. We smashed two rear windscreens trying to get it right. In the end we had to rectify the rear flat wall while not destroying the new interior, as it couldn’t be removed. Somehow it got fixed and only a light touch-up was needed.”

But it was the powerplant that caused Andy the biggest headache. “I had the engine ordered from America, but when it turned up it wasn’t anything like I wanted,” he says. “We had all sorts of dramas with it. I’ve lost count of how many times it’s been in and out of the engine bay; I’m so good at taking the engine out now I can get it out in one hour!”

Holden HZ One Tonner engine bayAndy experienced quite a few dramas with the motor. Imported direct from America, the Merlin big-block Chev landed not to spec and all out of whack. But after some loving from Fausto’s Performance Engines, the donk now makes the reliable horsepower he was after

Andy engaged Fausto and his team at Fausto’s Performance Engines to get to the bottom of things. They found that the crank wasn’t sitting straight, and the mill would need to be rebuilt. Once the team worked their magic, Andy hasn’t had to pull the motor once. “Other than a couple of little teething issues, everything has been smooth sailing since the engine has been fixed up,” he says. “Although, just the other week the front of the alternator chewed off. This is why my painter thinks the ute is evil!”

Holden HZ One Tonner engineThe engine is a 540ci Merlin big-block Chev that uses a Scat crank, AFR 335cc heads, Molnar conrods and SRP pistons. Andy says the HZ weighs about 1700kg, but with 587hp at the wheels (713hp on nitrous) the car is good for a quarter-mile of 10.2 seconds, even without the gas.

Power is sent through a fully manualised two-speed Powerglide to a nine-inch diff that uses 31-inch Moser axles and 3.7 diff gears. Getting the power up quickly isn’t any trouble thanks to a 4800rpm converter. A set of Center Line Revs occupy all four corners, wearing Nankangs on the front, and sticky 275-wide Mickey Thompson tyres on the rear.

Holden HZ one tonner interiorLeather covers just about every part of the interior, with the four-point rollcage painted in the same hue to make sure it blends in. If you look behind the front seats, there’s even a kick-arse sound system

Andy reckons that between with the weight of the tray and the Gazzard Brothers rear leaf-spring set-up, the ute rides and behaves very well on the street. The front end has also been rebuilt, and features Pedders front springs and 90/10 shocks. “For as low as it sits and given the weight of it, it’s a pleasure to drive,” he says.

Holden HZ one tonner dashAfter four years of hard work – from 2010 to 2014 – Andy entered the ute in Summernats 27 and achieved his goal of making the Top 60. Since then he’s gone on to win Best Ute at the Brisbane Hot Rod Show, as well as 40-odd trophies from other shows over the years.

Andy takes the one-tonner out every weekend, recently doing a 400km round trip. “The fuel tank takes around 100 litres and I get around 90-100km [per tank], so it’s not the best on fuel,” he laughs. “But I like to get it out as much as I can. Every year I take it to Powercruise for the weekend and give it hell; quite a few of us go. I think at some point I might build a car that can fit more people, though, because for me it’s all about sharing the experience with your mates.”

Holden HZ one tonner switchesANDY FENSOM
1977 HZ HOLDEN ONE-TONNER

Paint: Toyota Micra Red with candy concentrate

ENGINE
Brand: 540ci Merlin big-block Chev
Induction: 1100 AED carburettor
Heads: AFR 335cc
Camshaft: .750in lift, 264/272
Conrods: Molnar
Pistons: SRP
Crank: Scat
Oil pump: Melling
Fuel system: Aeromotive A200
Cooling: Alloy radiator, twin Spal thermo fans
Exhaust: 2in Castle Headers, twin 3.5in Magnaflow mufflers
Ignition: MSD

TRANSMISSION
Gearbox: Powerglide, manualised
Converter: Converter Shop, 4800rpm
Diff: 9in, Moser axles, 3.7 diff gears, full spool

SUSPENSION & BRAKES
Front suspension: Pedders springs and 90/10 shocks
Rear suspension: Koni adjustable shocks, Gazzard Brothers mono-leaf springs
Brakes: Wilwood discs with WB Girlock calipers (f & r)
Master cylinder: Aftermarket, twin 7in diaphragm

WHEELS & TYRES
Rims: Center Line Rev; 15x4 (f), 15x10 (r)
Rubber: Nankang (f), Mickey Thompson 275/50/15 (r)