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Six point Six SS

A SS Commodore ute with 6.6 litres of grunt and Harrop eight-throttle induction!

Words by Michael Knowling, Pix by Julian Edgar

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At a glance...

  • Ex-work SS ute
  • 402ci (6.6-litre) LS1
  • Harrop eight-throttle intake manifold
  • More than 460hp (343kW) at the wheels on pump fuel
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In recent years the Australian LS1 tuning scene has undergone a transformation. Not so long ago you were limited to aftermarket supercharger kits and, if you’re an atmo performance fan, a cam and heads package was your only option. How things change!

Noel X’s VY SS ute runs with the county’s best supercharged LS1s thanks to a lethal combination of cubic inches (402 of ‘em!) and all-out breathing enhancements. A Harrop eight-throttle induction system is the perfect crowning glory.

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Noel – the owner of a successful forklift company - purchased his SS ute brand new with the intent of using it for work purposes. A Redback twin 2 ½ inch exhaust, Pacemaker Tri-Y headers and a custom engine management tune helped ensure Noel was never late for appointments. Two seventy-five horsepower at the wheels made that a certainty.

But when Noel purchased a van for work purposes and ‘retired’ the SS ute, he decided to explore the potential that he always knew was lurking between the front suspension towers. The next mods are ones that NA LS1 fans know well – a cam and heads package. Noel opted for a 224 degrees duration camshaft, tickled alloy heads from Sam’s Performance and swapped to a shorter (3.9:1) diff ratio for improved response. On the Sam’s Performance chassis dyno, this upgrade yielded a 78hp (58kW) at the wheels gain bringing the total to 354hp (264kW).

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This was all pretty kick-butt stuff but six months later the engine was out. Not because of any mechanical failure, but because Noel wanted more grunt. After discussions with Sam, it was decided that the best way to go ahead was with extra cubes courtesy of a 383ci (6.3-litre) Lunati stroker kit. The Lunati kit increases swept capacity by more than 10 percent and the supplied pistons raise the compression ratio to 11:1. At the same time, a seriously big camshaft was slotted in and a Fast intake manifold went on top. The fuel system was up-spec’d with a Walbro in-tank pump and Holden supercharged V6 injectors and, of course, the engine was retuned to suit. Again, the diff ratio was shortened to a lively 4.1:1.

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This level of modification proved too much for the standard clutch so a heavy-duty organic single-plate unit went in and the six-speed manual ‘box was equipped with a Ripshifter. The standard SS ute suspension was also tweaked with lowered front springs, rear airbags (which help accommodate heavy loads), Koni dampers and a front tower brace. The ABS controlled anchors also slow things down better thanks to slotted discs and GreenStuff pads.

This configuration delivered massively improved torque throughout the rev range and a top-end output of 454hp (339kW) at the treads. With a pair of semi-slick tyres under the rear, the car managed a best ET of 11.9 seconds.

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At this point Noel caught a glimpse of the magnificent Harrop eight-throttle intake system and, well, it was love at first sight. Understandably. The existing Fast manifold stepped aside and the new Harrop manifold gave much improved throttle response and a smoother idle. Interestingly, there was only a minor power gain.

But there was no doubting the extra power to be achieved by the following mod!

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Once again, the engine was hauled out and the cubic inch count was elevated to a massive 402 (6.6-litre). This required boring the standard block and inserting huge 4 inch diameter sleeves. The pistons were again changed and the compression ratio remains more-or-less the same as previously – around 11.2:1. Given the extra torque achieved by the over-bore, a more aggressive camshaft (delivering around 270 degrees duration) was fitted. Those extra Newton-Metres also allowed the change back to a taller 3.9:1 diff.

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At the time of our photo shoot, Noel’s 402ci beast was still being run-in but subsequent dyno runs reveal the new engine can belt out more than 460hp at he wheels along with massively improved torque through the rev range.

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Noel hasn’t invested a huge amount in visual enhancement because the eye-catching factory green paint already does a great job attracting second glances. The only body mods are the fitment of Chev bowtie badges, clear lens taillights and a custom bonnet. Unlike many other custom bonnet treatments, this one looks genuinely tough without being kinda ‘out there’ – look closely and you’ll notice a Ford XR8 power bulge with a scoop neatly located toward the front. Judging by its appearance, the bonnet scoop is the same as fitted to a Subaru Liberty B4 twin-turbo - this scoop not only looks cool but provides extra airflow to the under-bonnet air filters. The final touch is the fitment of TAK five-spoke 18s wearing 235/40 Falken rubber. Very nice.

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Under-bonnet detailing includes a polished oil catch can, dipstick handle and coolant header tank lid – but, let’s face it, anything besides the wonderful Harrop manifold is just gravy... Inside, the trim remains standard Holden SS fare with the exception of a Pivot shift light to warn when the big 402ci bruiser is spinning close to its 7000 rpm limit.

At the time of writing, Noel hasn’t had the chance to run the car down the quarter mile in its current configuration. However, with traction permitting, it should run a very low 11 second pass – Noel says maybe an 11.1. Of course, when you’re that close to running a 10 second ET it’ll be almost impossible to call it quits.

Tens without forced induction or nitrous? Yep, it is possible...


Sam’s Performance +61 2 9772 3105

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