BLOWN BLUE SIX
> MATT WATTS GIVES THE MIGHTY HOLDEN SIX IN BLO202 A FRESHEN-UP
Learn the secrets of BLO202’S tyre-frying Holden six-pot
THOSE of you who love burnouts should be no stranger to this car and its 29-year-old driver, Matt Watts. Matt has been cruising and abusing this Torana ever since he got his licence. Inspired by photos he’d seen of his dad’s LC XU-1 as a kid, Matt dragged this one home from country Victoria at the tender age of 16 and proceeded to hot it up, firstly with a very tough, circuit racing-spec naturally aspirated combo before upping the ante and adding a blower about four years ago.
“Everything I’ve focused on has been to make it go better,” Matt says. “When I was 20 I built the first engine for it, a pretty cracking naturally aspirated set-up with triple carbies – a full touring-car, race-spec engine – but after going to Summernats a few times, I got the bug to step things up a bit more. There weren’t a lot of blown sixes getting around – which I liked because I like being a bit different – only really Adam Slorach’s NUMNUTZ and Benny Falk’s SIXPOT. There’s a Street
Machine photo of a red Torana that used to get around Sydney with a blown six in it. I had a picture of that on my wall [see sidebar, p.
111]. I was just so taken by it as a kid because it was so different.”
All those improvements worked well for close to 11 years – six of those with a blower – before the old combo finally cried: ‘Enough!’ at Brashernats earlier in the year. Still, it was pretty amazing it lasted that long with nothing more than Starfire rods and a set of ACL race pistons doing all the heavy lifting. “I was never trying to push it too far, always kept things fairly safe and never tried to make a horsepower number,” Matt says. “It was reliable as all hell up until then; I’d only ever been towed off a pad once before because I broke a blower belt.”
Understandably, Matt wanted to make sure the new combo was built to withstand whatever he threw at it. To make a Holden six live at high rpm you’ve got to worry about the oiling side of things more than anything, so Matt turned to the guys at Octane Alley in North Geelong, who handled all the machining and assembly and are old speedway gurus. “They know their way around an old Holden six and have a few tricks that they do there to do with the oil pump and oil flow through the block,” Matt says. “A bottom-end girdle is a big thing as well, as Holden sixes like to separate main caps.
“The main difference from the old combo is that the bottom end is totally built for boost,” he continues. “It's a blue block with Spool H-beam rods, custom CP forged pistons and a little bit of grout in the block. I didn’t want to throw too much in it, because doing what we do with the burnouts, you want every bit of cooling you can get.
“The other problem you can run into with too much grout is the oil returning back down the block. Holden sixes have a tendency at high rpm to pump all the oil to the top and starve down the bottom, so to prevent that we’ve put restrictors in the pushrods and every oil gallery has been drilled out or polished or the edges cleaned up to promote oil flow throughout the block. That’s one of the big reasons why mine lives. It’s still a Holden crank; there are people that make billet ones now, but cost-wise I don’t see the benefit,
AFTER GOING TO SUMMERNATS A FEW TIMES, I GOT THE BUG TO STEP THINGS UP A BIT MORE
because the biggest weakness is the block. The valvetrain and head is pretty much the same as before.”
One other area that involved a lot of development was the intake manifold. As you can see, it’s pretty impressive – both in design and size – and was designed and fabricated by Brett at BNR Engines.
“It’s a bloody good design and it really does work,” Matt says. “There was a lot of trial-anderror with the 4/71 getting even distribution to the ports. With an aspirated six-cylinder you tend to lean out number one and six cylinders, but with the blower on top it seems to push the air and fuel to the outside, so the outer runners seem to get favoured. The design with the middle runner coming off the bottom of the plenum and being the same length as the end runners, I’ve never had an issue with lean-outs and I get really good, even mixtures across all cylinders.”
Matt did consider stepping up the camshaft and maybe getting some more revs out of it, but he didn’t want to step away from how reliable the old motor was. “Why change what works?” he reasons. “It will hold top gear on the limiter at any pad in Australia, and I’ve been able to push the little six up into finals against Masters-quality cars and been able to push the big boys in the V8s.”
WHY CHANGE WHAT WORKS? IT WILL HOLD TOP GEAR ON THE LIMITER AT ANY PAD IN AUSTRALIA
Just before Motorex this year the car had a full respray, and it was tubbed to fit a 15x10 with a 295 – a pretty big tyre to stuff under a little Torana
Matt didn’t want to stray too far away from the oldschool Holden origins, hence the red – okay, Chevy orange – paint and finned rocker cover. It even runs the standard distributor, although timing is controlled via a Mallory Hyfire VI ignition system that allows you to retard timing as boost increases A good oiling system is essential in keeping any engine alive, so internally every oil gallery has been cleaned and the oil pump blueprinted. The sump has been modified to relocate the oil pick-up, as the stud girdle means you can’t run the stock pick-up. There are also baffles and trapdoors to make sure the oil is always available, with the added benefit of some extra capacity