Street Machine - - Contents -

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,


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.”


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

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