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7-SECOND HEMI-SIX POWERED CHRYSLER CENTURA

By Scott Taylor | Photos: Chris Thorogood, 04 Dec 2016 Features

7-SECOND HEMI-SIX POWERED CHRYSLER CENTURA

Andrew Sanders's JUSTA6 Chrysler Centura has evolved from humble street car beginnings to wild seven-second race car

THIS story on Andrew Sanders's JUSTA6 turbo Hemi six-powered Chrysler Centura was originally published in the September 2014 issue of Street Machine magazine. 

THIRTY years qualifies as a long-term relationship in our books. That’s how long Andrew Sanders has been driving and tweaking his six-cylinder Centura. “It was my first car,” he says. “I bought it as a 245 and four-speed KB Sports Pack, the one with the blinker on the left-hand side. It was blue with a white stripe. I went for my licence in it.”

Chrysler Centura Turbo Hemi JUSTA6 7Back then a Centura could be had for a couple of grand, and replacing the economical 245 with a fire-breathing 265 Hemi was the quick and cheap way to maximise bang-for-buck, as Andrew discovered.

“Our family were always Chrysler people, and it didn’t take too long before I pulled the original engine out and put an E49-spec 265 with triple Webers in it,” Andrew says. “It ran 13.5@100mph!” That mightn’t sound impressive, but back then it was quick for a naturally aspirated six-cylinder. “Then the old drag racing bug bit me and it’s been biting ever since,” Andrew reckons. “The Centura used to be my daily; I’d drive it everywhere, and then drive to Heathcote to race on the weekends.”

Chrysler Centura Turbo Hemi JUSTA6 3Things changed when he bought his first turbo, “I found a T04E turbo for $120 at the Bendigo swap meet,” he says. “I’d always been interested in turbocharging, so we made a rough set-up using a cast-iron manifold and we hung a single Weber off the front. We went out on the road, no wastegate, no nothing and ran it through the gears before we popped the head gasket on every cylinder. But we were just shaking, thinking: ‘Wow!’”

Chrysler Centura Turbo Hemi JUSTA6 4Andrew’s brother had a supercharged 265 that was pretty quick back then, but the potential of the turbo had them rethinking their priorities. They built a homemade wastegate using the exhaust port of a sliced-up Hemi six head. “My brother was older, so of course he reckoned he knew everything, but the wastegate was my idea and the thing just flew. So then he started to listen to me a bit more.” From there they started playing around with water and methanol injection with Hobbs switches, and changed to a Holley carb just because it was easier to tune. The Centura quickly made a name for itself as a seriously quick street machine running 12.2@116mph.

Chrysler Centura Turbo Hemi JUSTA6 1Naturally the extra horsepower proved too much for the old BorgWarner single-rail four-speed, and they switched to a Powerglide as they couldn’t get a transbrake for a Torqueflite back then.

“At this time we were doing a lot of development on the chassis dyno with Alby Lamb at Howe Automotive in Daylesford. We’d try something, go home and play with it for a few weeks and then go back to Alberts. We worked out these dynos were a good thing, and we were making decent gains. We’d make an extra 50hp and then another 50hp, and then we started breaking everything. But when I put the ’Glide in, it made 70hp less at the tyres and I was devastated.”

Chrysler Centura Turbo Hemi JUSTA6 9At the track it was a different story. The car was running 11.2 with the manual; it went 10.8 on its first pass with the auto and eventually ran 10.4 at Calder in that configuration.

“That was just when I started my business, Specialised Power Porting, so the car got parked for a while after it hurt some pistons,” Andrew says. By then the Chrysler was no longer a street car, the boys having fitted a tilt front, bigger tubs and a home-built ’cage. It was wearing a pastel-green hue, but once Andrew’s business was up and running the Centura was the perfect billboard, so he hit the track again. He decided to up the ante with mechanical methanol injection and a massive turbo to replace the old T04E that he used to run.

Chrysler Centura Turbo Hemi JUSTA6 Engine 1“We were actually killing a few turbos due to oil contamination. The old Z9 Ryco was bypassing the oil above 4000rpm, so we changed the oil filtering system and started filtering the oil to the turbo as well,” Andrew says. “The big turbo came off a 900hp diesel generator on the Abel Tasman. It had a 90mm inducer and a massive turbine housing and made boost at 3500rpm. I’d still like to run that turbo now, but we damaged it at Calder years ago. The T04 used to run out of steam at the 1000ft mark, but this thing just kept on punching through all the way past the finish and it ran high eights.”

Chrysler Centura Turbo Hemi JUSTA6 Engine 3But that was then. What you see today is the result of at least 20 years’ development, and Andrew pulled the whole car down again a few years back and rebuilt it from stem to stern. All the old ’cage and sheetmetal was cut out and replaced with fresh chrome-moly tubing and new tinwork.

Chrysler Centura Turbo Hemi JUSTA6 Engine 2“It was pretty rough back in the day,” Andrew says. “I wanted to neaten the car up a bit, but I ended up going all the way.”

One thing that hasn’t changed is the Hemi six. Alright, so all the bits are different, but she’s the same old motor underneath. The engine still uses the factory block, crank, cast-iron head and timing cover, but they’ve all been customised to meet Andrew’s requirements. The block has been machined for a 90mm-thick pan girdle that works with custom main caps to stiffen the block and retain the crank. It’s also been machined to accept a couple of extra cam bearing journals to stop the cam snapping in two. Aluminium GRP rods soften the blow to the crank journals and they work with Diamond pistons to handle about 200hp per cylinder.

Chrysler Centura Turbo Hemi JUSTA6 Interior 3Yep, this six-banger makes around 1200hp, and with an Autronic ECU running the show the Centura has stormed down the strip to a best of 7.88@171mph – and Andrew reckons there’s more to come.

Chrysler Centura Turbo Hemi JUSTA6 Interior 2The turbo is a Precision GT4788R hanging off one of Andrew’s own turbo manifolds and it pumps about 33-35psi boost into a custom intake, also of his own making. Apart from the block machining by Dandy Engines, the MDT transmission and the custom paint, Andrew has done just about everything himself. It’s about saving a buck where he can. “We had plenty of time back in the day, but not much money, so we’d do everything ourselves. Whereas now I’ve got no time, and no money,” Andrew laughs.

Chrysler Centura Turbo Hemi JUSTA6 10Despite that, Andrew plans to eke a few more horses out of the Hemi and hit the mid-seven-second zone. To aid him there’s a new billet aluminium head in the build and he’s planning some turbo and cam changes as well.

But one thing definitely not changing is the old Hemi six. “I don’t think it’s been developed to its full potential,” Andrew says. “They’re an old dinosaur engine, but they’re still a good thing. I’ve never owned a V8, and while I know we could make some serious power with one, I like to be different and develop things myself. I’ve never been one to follow the herd.”