Joe Zullo’s eight-second, naturally aspirated Holden 202-powered dragster

Joe Zullo’s eight-second modified dragster became the fastest aspirated Holden six-powered car in Australia at this year’s Winternationals

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Photographers: Joseph Hui

We Aussies are famous for our ingenuity, and nothing exemplifies that more than the many clever people involved in the drag racing industry.

First published in the October 2024 issue of Street Machine

Take this bad-arse dragster, for instance, built by veteran Sydney racer Joe Zullo. Powered by a naturally aspirated Holden 202 six-cylinder, this beast has run a best of 8.39 seconds over the quarter. And at the 2024 Winternationals, it set a new national speed record of 168mph in the B/MD class, making Joe’s dragster the fastest aspo Holden six-powered car in the country!

Getting the car to that point has taken more than two decades of evolution and development.

“I built the car back in 2000 with help from my cousin, Angelo DiBella, in his garage,” Joe recalls. “We made the car as long as we could to fit in the garage, which ended up being a 180-inch wheelbase. We built it to take a supercharged motor and set our goals on building the quickest six-cylinder Holden in the world, but initially the car had a naturally aspirated engine. We started with a ported factory cast head, and eventually fitted a Phil Irving head.”

Unfortunately, that head didn’t work out as well as Joe had hoped, so he decided to go straight to a supercharged combo. “I begged and pestered Frank Duggan for a cylinder head, and eventually he agreed to do it,” he says. “I never thought I would end up buying his company! It’s now branded J.ZED Holden 6 Performance.”

In 2003, the J.ZED rail ran a record-smashing PB of 7.7@168mph with the blown engine. But after having some blow-by issues with that combo – resulting in Joe being showered with oil every pass – it was time for a change.

Joe decided to aim for the naturally aspirated B-Modified record, building the aspo Holden six that remains in the car today. With the 202 in place, he broke the class record in 2009 with a 9.0@145mph pass.

Buoyed by that result, Joe’s next step was obvious: “We wanted to make the first aspirated eight-second pass in Australia. We were just loving the aspirated deal, and we eventually got the car into the eights.” Joe’s continual development of the 202 over those years culminated in that aforementioned 8.39-second PB, set at last year’s Winters.

So, what’s inside this little engine that could? Joe began with a Holden 202 six, which he grout-filled to the top of the block. The stock-stroke 3.25in crank has been upgraded to a custom, 3.6in-stroke, 4340 steel crank, bringing the engine to 228ci with a 40thou overbore. The factory 5.25in rods were swapped out for 5.63in Manley items, which increased torque due to the additional dwell time on top dead centre.

The real magic, of course, is in the alloy cylinder head – the Duggan-derived design that Joe now proudly owns and manufactures himself under his J.ZED banner. Holden-six nuts will know that there are no other heads like these. The factory valve location is off-centre and toward the sparkplug location, but the J.ZED head has the valves placed in the centre of the cylinder, positioned vertically instead of the factory angled placement. This means that cams with more than .500in lift can be used, as the valves won’t hit the bores like they would in a factory head. Valve size has also been increased to 1.9in on the inlet and 1.5in on the exhaust. Yella Terra custom built a set of 1.7:1 rockers for the head, and the camshaft is a Tighe solid-roller of undisclosed specifications. The block is O-ringed, and the 14.5:1 compression is sealed in with a copper head gasket and ARP studs.

Following a catastrophic failure on EFI when an injector stuck open, Joe went back to mechanical alcohol injection with a Hilborn pump, and has never looked back.

While the engine has no problem buzzing to 9500rpm, the head won’t make power to that point, so revs are kept to a still-prodigious 8000-8500rpm, depending on which transmission the car is running. That requires a great oiling system, and Joe has gone with a four-stage dry sump affair.

The car used six-coil ignition until recently, but it’s currently running ‘borrowed’ ICE ignition, which Joe says works unbelievably well for such a simple system.

As for transmissions, Joe’s tried a few over the years. “We have swapped between a three-speed Trimatic and a Powerglide, both prepared by Craig’s Automatics,” he says. “The two-speed we run now is not ideal for our set-up, as it has an unfavourable low-gear built for the supercharged engine, but it gets the job done.”

Other recent changes include swapping the Ford nine-inch rear out for a HiLux diff. The HiLux rear is lighter, but its real benefit is that it creates more room for Joe in the cockpit.

On the Westend Performance dyno in Western Sydney, Joe’s Holden six made an impressive 498hp and 390lb-ft at 7800rpm. “We have since tried a few changes to this combination and feel we are now at somewhere around 530-550hp,” Joe says. “Testing has made us realise that sometimes less is more. For example, we were running big throttlebodies, which we thought would work, but when we choked them down from 2¼in to 2in, the car went quicker. This tells us the head needed more air speed through the ports.”

Weighing in at just 1300lb, this dragster is a racer’s dream, and Joe and his team just love tinkering with it and refining it. “I could show some self-control and go and win some bracket racing, but I just want to keep running quicker,” he laughs.

To achieve that, Joe says the next change for the car will be the addition of a tunnel ram. And in the background, he’s also in the process of building an FJ sedan, which he plans on running nines with – powered, of course, by one of his signature aspirated combinations.

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