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Loose unit: 1969 Chevy Camaro Z/28

17 May 2015


The original plan was never to build a nine-second streeter, but sometimes, you can’t argue with fate

Unless you’ve been living under a rock for the last few years, chances are you would have heard of the names ‘UNIT’ and Aaron Costello. The car has become one of the better-known Camaros around, and at a time when it seems like every second car is a Camaro, that’s pretty tough work on its own. Of course, Aaron never intended for it to be that way. In fact, when the car was first purchased seven years ago, he wasn’t intending on buying a Camaro at all.

A builder by trade, Aaron had his heart set on the latest Commodore at the time. However, the long waiting period between when he’d have to hand over the cash and when the car would finally be in his possession was just too much for him to take. Already having spent the cash in his mind, he did the next best thing, and that was to buy the American car he’d often dreamed about owning.

A quick look on the net found just the thing: a big block–powered Camaro, painted in a gorgeous silver metallic. Sure, he had to wait for the car to arrive too, but at least he knew it was on the water, and since it was being sold through a reputable car dealer, he knew what he was getting …

The time waiting for it to arrive was spent telling his mates of the beautiful machine, complete with plenty of power and a flawless finish. Of course, once it landed and was rolled out of the container, his excitement nearly turned to tears. The car had come loose during transit, and had sailed across the ocean bashing back and forth against its steel tomb. It was all fixable though, thanks to the team at Advanced Auto Painters in Paeroa. Sadly, the panel and paint issues weren’t the biggest of the problems, as, once fixed, you’d never have known it had ever been damaged. 

The bigger issue was that as the car had been picked up by a forklift, not only were the headers all bent up, but the sump was punctured too. The big issue with this was that the hole in the sump exposed the “four-bolt mains” block to be just a stock two-bolt set-up. Pretty heartbroken by this point, Aaron was wishing he’d held out for the Commodore. But not one to back down, he was never going to admit defeat.

When talking to friend and well known engine builder / drag racer Rick Kerkhof, Rick suggested he just freshen up the 454 and flick it off. This was followed by the suggestion he replace it with a GM ZZ572 crate motor, which, if that couldn’t put a smile on Aaron’s face, nothing would be able to.

Within two weeks the holy grail of GM big blocks had arrived, and Aaron was more excited than a kid at Christmas once again. With the motors being rated at 620hp, and built as strong as an ox, there isn’t much better on the market as far as tough street car engines are concerned.

His love of the car’s newfound performance soon saw him testing it down the drag strip. Despite a best time of 11.0 seconds, he eventually became used to the power and it was no longer enough to keep him excited. Forced induction was what it needed, in the form of a ProCharger, of which Aaron opted for an F2 item running 10psi boost. 

Of course before getting to this point, he’d played with many other aspects of the vehicle, such as the suspension where he had a three-link rear end custom-fabricated by the team at Mitchell Race Xtreme. The car was also mini-tubbed, and a set of impressive Wilwood brakes fitted amongst other things. Good friend Steven Purcell has been there all the way through, and Aaron can’t thank him enough for all the help he’s given along the way.

Once the ProCharger was sorted, the excitement was back, and Aaron’s love for racing was ever increasing. He soon became a regular at the annual Father’s Day Drags, as well as events like Powercruise, and after running a new PB of 9.6 seconds at 148mph the car became well regarded as one of the toughest street cars in the land. And it still is. 
The fun all came to a rapid gut-wrenching end though, when substandard fuel was used at the drag strip. Despite shutting it down as soon as he heard a noise that wasn’t right, it was too late. A piston had a hole in it, and the car was trailered home. 

Aaron says his thought at the time was, “I guess now that we’re pulling the engine down, we may as well build it to suit the ProCharger, as the 572s were never designed with boost in mind.” Rick would once again be the man for the job and it wasn’t long before he had the engine in bits, and then disaster struck. “Three days out from Christmas I got a call from Rick saying his shed had burnt down, with the engine in it. The only good things were that all the aluminium bits were away getting polished at the time, and the fire > brigade put the fire out before it got too hot in there, so the damage was mainly from water,” Aaron says of the unexpected drama.

With Rick’s shed rebuilt, he got back into the engine, and fitted it with new 8.7:1 pistons and a blower cam. The stock block was OK, as were the rods and crank. The heads were then fitted with new Milodon valves and springs before the stock intake was refitted along with a 750cfm Holley blow-through carb. “It’s still got the $20,000 rocker covers,” laughs Aaron, about the new set-up. 

As you can imagine, keeping a set-up like this running takes a fair amount of fuel, and a decent amount of spark too, so Aaron’s fitted a MagnaFuel pump and regulator as well as a bunch of MSD ignition gear to make sure there’s no shortage of either. Currently a boot-mounted 45-litre fuel cell is fitted, but with the car seeing more and more street miles, that’s all about to change. With the addition of a stock fuel tank, the current twin three-inch exhaust system will be modified to exit either side of the tank. It’s a small sacrifice, but one that Aaron’s happy about making, because if it weren’t for the support of his long-suffering partner Alicia and his kids, he wouldn’t be able to have the fun he does.

With street driving always on the agenda, keeping the coolant temps under control has been a top priority, and it’s one that’s taken a bit of doing. With the current PWR radiator set-up though, Aaron couldn’t be happier — even if it took him a few substandard radiators before he bit the bullet and paid the PWR asking price. Behind the grille area of the car, it’s pretty full, as forward of the radiator is also a large air-to-air intercooler and an equally sizable trans cooler. 

The other end of the trans lines are connected to a heavily modified TH400 transmission with 3200rpm stall convertor and full manual valve body. Further back you’ll find a 12-bolt diff with a 3.55:1 ratio and a driveshaft Aaron’s been told is good for 3000hp … should the need ever arise.

As it sits, the car has made a dyno-proven 805hp at the wheels, which Aaron is hoping is enough to get it down into the low nine-second mark, if not into the eights. With sticky Mickey Thompson slicks fitted come drag season, there’s no reason why it can’t happen. Of course, try and lay down any real power on the 20×15-inch street rims though, and all you’ll get are 355mm-wide black marks on the road … not that Aaron’s complaining, mind you!

So how does it drive? Well as you can probably only imagine, on the road it’s insane, criminal almost, with just how fast it can accelerate — when you want it to, that is. Under light throttle and off boost, it cruises effortlessly. Which is how during Beach Hop this year, Aaron managed to go through a ridiculous amount of fuel, driving it as often as he could, usually with the whole family on board. Aaron says the biggest improvement to its drivability though, is the recent fitting of power steering. Prior to this, it was hard work on the arms, but now it’s a really nice car to drive.

With the engine set-up now happy to take all that Aaron can throw at it, he’s looking forward to getting it back on the strip to see what it can do. More than that though, he’s looking forward to loading the kids in the back and going cruising as often as he can. 
Ladies and gentlemen, street cars don’t come any cooler than this! 

Aaron’s Camaro was featured in NZV8 Issue No. 98 (July 2013). You can grab a copy here


  • Engine: 572ci big block Chev, JE pistons, 8.7:1 compression, blower cam, Milodon valves, Milodon gear drive, ported heads, custom valve springs, Holley 750cfm blow-through carb, ProCharger F2, 10psi boost, MagnaFuel fuel pump, 45-litre fuel cell, MSD Digital-7 ignition, twin 3-inch exhaust, Coby resonators, Flowmaster mufflers, PWR custom radiator
  • Driveline: Modified Turbo400 transmission, 3200rpm stall converter, full manual valve body, 12-bolt diff, LSD head, 3.55:1 ratio, C-clips
  • Suspension: Hotchkis sway bars, Hotchkis front springs, Bilstein shocks, custom three-link, QA1 coilovers
  • Brakes: Wilwood pedal box, Wilwood six-pot front calipers, Wilwood four-pot rear calipers, cross-drilled and slotted rotors
  • Wheels/tyres: 18×8.5- and 20×15-inch Intro V-Rod wheels, Toyo Proxes front tyres, Mickey Thompson rear tyres
  • Exterior: Competition Engineering mini-tubs, metallic silver paint
  • Interior: RCI seats, SAAS carbon steering wheel, Hurst shifter, Auto Meter carbon face gauges, eight-point rollcage, Sony audio
  • Performance: 805hp at the wheels, 9.60-second quarter-mile