Despite the venerable Holden six-pot nearing 60 years of age, there is no shortage of maniacs still playing with them for use on the street, strip or burnout pad. There are plenty of fast ones around, but in terms of pure, 100 per cent street-driven Holden sixes, few have impressed us more of late than Trevor Owen’s unassuming LC Torana. Is there a quicker, street-driven, normally-aspirated Holden six on pump fuel and street rubber out there? If so, we’d love to hear from you.

“I’ve done performance stuff my whole life,” says Trevor, who’s based in Toowoomba, Queensland. He mentions a gaggle of small- and big-block Chev V8s, Fords, crazy little Datsun fours, and – of course – Holden sixes and V8s. “Anything with a carby, that’s my passion,” he says. “In fact, I got the nickname ‘Captain Carby’ from some of the stuff I used to do.”

About five years ago, Trevor was having a few beers with a couple of mates. “I said, ‘You know what? I reckon I can put a little 202 naturally aspirated, street-registered Torana into the 10s. Well, I tell you what, my mate spat his beer all over and the other fell off his stool. So I bet ’em a six-pack!”

It wasn’t just the bet that motivated Trevor. He’d been thinking about a Holden six build for a while, having already fashioned a hot Holden 202 six for Toowoomba local Bob Power – dad of Will Power, of V8 Supercars and, more recently, IndyCar fame. “I built them a good quick little Holden six years ago,” Trevor says. “It has all the good gear in it; it’s a very reliable, very fast thing. But it’s a circuit engine, so it’s smaller in the cam so there’s more acceleration out of corners.

“I remember thinking back then, ‘With a bit more power, this would be a 10-second street motor.’ So that idea has always stuck around.”

The quick six-pack idea was also viable thanks to the continuing availability of the Duggan-type high-performance alloy head for old-school Holden sixes. Designed by Frank Duggan decades ago for methanol-injected speedway engines, a revised version of his high-port design is these days manufactured by racer Joe Zullo under the J-Zed banner.

It all added up, so Trevor got busy, basing his engine on a Holden block that’s been half-grout-filled for strength. “With big power, these things can crack right up through the guts of the block,” he explains. “Like, pull them out, give them a kick and they fall apart!” For similar reasons, there’s a mains girdle to reinforce the bottom of the block and keep the crank in line.

Scat H-beam rods, JE pistons and a one-off, offset-ground 4340 billet crank fill out the bottom end. Holden sixes don’t have a particularly good stroke/rod length relationship for big revs, but this one is good for 8000rpm.

Feeding that J-Zed alloy head is a set of sidedraught 50mm-throat carbies. Surprisingly, they’re copies of Webers, sold under the FAJS banner. Trevor seems to have them jetted and running okay. With the nickname Captain Carby, we’d expect nothing else!

Plenty of development and dyno time has gone into other aspects of the E85-fuelled engine’s breathing, too, with 3D-printed plastic intake trumpets on the suck side and a handmade 1¾-inch primary-piped exhaust after the big bangs. The roller cam has 700thou valve lift, but according to Trevor, “it sits there idling at 700rpm, smooth as silk. Most people who hear it don’t believe it’s anything special. But the story changes when you stand on it!”

Wrapping up the radical red is an ICE ignition system and a modified lube system that retains the standard sump but feeds the oil pump externally.

Deciding what car to place the staunch six in was easy; it was always going to be an early Torana. “My first car was an LC Torana when I hit the road in 1980,” Trevor says. “It had the 202 and the SUs – you know, the usual formula!” he laughs.

Nearly 40 years later, karma handed Trevor a bargain when a customer mentioned he had a Torana that he was to have repowered with a V8 but had changed his mind. “It was a lovely old thing – an unfinished project, but all there, which I had to do hardly anything with except for paint. I was around there with the tilt tray and the dollars right away!”

Also impressive is the fact that this car runs a Trimatic auto behind the stout six. Yep, Holden’s modest – and often teased – family-grade three-cogger is what’s feeding the mill’s 400-plus ponies to the pavement. It’s not standard though, being the work of Toowoomba’s Tricky Trev’s Transmissions. A 10-second Trimatic is a big kiss of encouragement for anyone chasing performance from an auto Holden without the effort of transplanting a Powerglide or a TH350/400 ’box. There’s also a transbrake – that Trevor is yet to take advantage of – and a tough Toyota HiLux rear end with steep gearing.

Is there a quicker, street-driven, normally-aspirated Holden six on pump fuel and street rubber out there? If so, we’d love to hear from you.

With the combo sorted, Trevor was a little nervous about unleashing it at Willowbank Raceway:

“It had been 30 years since I had been on the track. Back then, I was running low 12s in my four-speed HK 327 GTS Monaro. So the Torana was a bit daunting! But it all came back to me as soon as I hit the burnout box. The lights turned green and it was like a truck had hit me from behind. But she hooked up perfectly, running 1.58 to the 60ft and crossed the line at 11.10-second first go. Then it was back on the dyno for a bit more development. The ram tubes my son Sam made on the 3D printer were a key to getting into the 10s, along with some suspension tweaks.”

The end result is a no-boost, carb-fed, legit streeter that’s run a best of [email protected] – all powered by a Holden six built off the back of a bet.

“I’ve put a lot into this engine,” says Trevor, “so the boys owe me that beer! This little car has really reinvigorated my passion for going fast again, just like in the 1980s.

“Now I’m going to give is a freshen up, after a year of racing. I’ll do a little more development and see if we can get a couple more tenths out of it. Here’s hoping!”

RED HOT TIPS

TREVOR’S own engine is next-level, but he has some good advice for anyone wanting to build a toey street Holden. “I find it’s best to use a blue or black block,” he reveals. “There’s no real difference, but they’re younger so are likely to be in better shape – for instance, not ruined by lack of coolant.”

Trevor has a J-Zed head on his, but as for factory heads, he reckons a highly modified nine-port item is the ultimate for power, while the blue/black 12-port head is the pick for the street.

The later blue/black 3.3-litre motors have a counterweighted crank, so it’s the better choice for a smooth, powerful street Holden six. “These later engines’ standard rods with ARP bolts will suit most street engines,” Trev says.

Trevor suggests conrods run at 2.20-2.50 thou and mains 2.80 to 3.25-thou. He reckons roller rockers and good pushrods are always a great investment, too.

As for carbs, Trevor suggests a 350 Holley if you’re on a budget. SUs and Webers are more expensive, but also more effective. “Triples are still the holy grail; 1¾-inch SUs or 45mm Webers will cater for nine out of 10 street performance or track cars,” he says.

Finally, for the exhaust system, Trevor recommends tri-Ys up to 1.625-inch primaries with a 2.5-inch pipe.

TREVOR OWEN
1971 HOLDEN TORANA

THANKS
My mate Ash Low for panel and paint, Nick and Sam Owen, J Tune, All Torque Engines, Bob Falknau, Gazzard Bros, Joe Zullo, RE Power, Muffler Kings & Rob and Bruce for the challenge incentive!