SINCE around 2012, it has gone from running eights to now being on the verge of its first six-second quarter-mile pass.
Watch the video: Steve's Pro Line 481X-powered XW Falcon
The most recent engine combination was a 427ci small-block Ford with twin Precision turbos built by Frank Marchese from Dandy Engines, who runs a similar set-up in Dandy’s XW Falcon. That same motor combo saw Bezzina’s car run a best of 7.08@203mph on 275 radials, untubbed and with a fairly basic leaf-spring rear end set-up by Profab Motorsport Fabrications. But they found the limit of that engine combo when they split the block into two pieces.
From there they scratched their heads, pondering where to go next. At this point Steve wanted to have the quickest stock-bodied leaf-sprung car in the country, so they decided to go with one of the toughest engines you can currently buy: the Pro Line 481X. And of course Frank from Dandy is the guy to speak to about 481X motors here in Australia, so it was a logical decision.
The 481X is the brainchild of American drag racer Alan Johnson, and was designed after all the five-inch bore-space motors came onto the scene and dominated everything. The NHRA gave racers running those engines a significant weight penalty, so to get around this Alan came up with the billet-alloy 481X. The 481X is a symmetrical-port big-block Oldsmobile/Chev-based motor with a 4.84-inch bore space, but with improvements to the cam core and lifter spacing.
And they are virtually indestructible, with the block and heads each hewn from a solid chunk of billet alloy. Frank describes it as being the “nastiest, most bad-arse engine you can get.” Alan Johnson Performance Engineering creates the block and cylinder heads, while Pro Line supplies the rest of the parts required to put it together and make it work.
The result is a motor that can comfortably make upwards of 4500hp out of anywhere between 520 and 570ci – depending on spec – when paired with a turbo or blower set-up. In fact at various points in time 481X motors have claimed records for the fastest and quickest turbo-powered cars in the world.
So what is one of these engines doing in an old XW Falcon with leaf-spring suspension and radial tyres? Well Steve wants to comfortably and consistently run sixes at 3500lb, so after weighing up the options, the guys decided it was the best way to go.
Naturally the billet-alloy 481X is a much bigger motor than an old small-block Ford, so getting it to fit was easier said than done. The boys from Profab Motorsport Fabrications made it all work, but they had to cut out the factory shock towers and make it a strut front end to give a bit more wiggle room. Yep, everything with these motors is big – from the heads to the intake manifold and 2.5-inch primary pipes.
Watch next: Six-second Pro Line 481X-powered 1969 Camaro
And for big cubes you need big turbos, and Steve’s 540ci motor rocks the same pair of Precision 88mm snails.
All up, it took a month for Profab to get all the fabrication work done and another month for Rhys Richards from Dandy Engines to assemble the whole car, track-ready.
The boys had it mostly buttoned up for MotorEx in Melbourne, but only just had the whole deal sorted and running the way they wanted for Grudge Kings, where Steve made his first few test hits with this set-up.
Frank from Dandy as well as Jamie Miller from Pro Line in America were on deck to assist with tuning the FuelTech ECU, and the signs were very promising early on. The car went 7.81@127mph within its first couple of passes, backing off and pulling the ’chutes three seconds into the run. By the end of the test day they’d gone 7.1@171mph, again off it early and pulling the ’chutes at 1000ft. Those sixes can’t be far away!
As you would expect from an engine that is made from a solid chunk of billet alloy, not to mention the research and development that both Alan Johnson Performance Engineering and Pro Line have put into it, the 481X is not cheap. Frank reckons a used motor like Steve’s will cost between $60,000 and $70,000 here in Australia. Even though the block doesn’t have water jacketing for a cooling system, Steve plans to cruise it occasionally, as the alcohol fuel burns cool enough at low rpm for it to not overheat.