The Toyota Supra and the JZ engine go together in tuner folklore like a beer at the footy, so why the hell does Ross Harris have an LS in his?

That story began the way all should: a few mates in a shed, beers in hand, scheming new ways to go quicker. “The 7M that the car came with was really tired, and one night my mates were daring me to LS-swap it,” Ross says. “So, I found a crashed V8 VY wagon on Marketplace and jumped on it.”

As you can imagine, an LS into a Supra is not exactly a common swap, so Ross needed to get a few things sorted to install the GM donk. “I found some billet mounts online, and we had to change to a rear sump,” he explains. “Headers were a bit of a nightmare, too. I actually copped a lot of hate from the Mk3 Supra clubs – I even got some proper hate mail!”

Ross eventually got it all running with a toughened-up 4L60 and the LS ECU and wiring, and then hit the strip. “I’d never really drag-raced before, but it went 12s on the first day, and from there I was hooked!” he says. “I guess that’s when things started to escalate.”

Research began on potential power adders, and having observed the successes of Drag Challenge veterans Luke Foley and Mark Drew with their turbo LS combos, Ross knew what he wanted. “I also ended up speaking to Tony Webb about a rear turbo set-up, and he was great in advising me to get the STS rear turbo kit from Summit Racing,” he says.

With the good help of Ross’s mate Matt Robinson, a rear-mount turbo kit was fabricated to suit the Supra. “Space in the engine bay was tight, so it was more about dealing with that than anything else,” Ross says of the rear set-up. 

The Supra ran a 10.70@132mph back at Heathcote with the turbo kit installed, but trouble struck not long after. “We got near-on 1000hp out of that LS on the dyno, but then it finally broke,” says Ross. “The plan then was to build the 427ci Dart LS Next I have here for it and do it all right this time, but then this LS3 popped up.”

With the full-fat Dart build taking a while to piece together, Ross elected to slap together the LS3 for the Supra to get it ready for Drag Challenge 2024. The bottom end is standard, with the rings gapped to suit boost. Mods include a VCM16 camshaft, upgraded valvetrain, and Blackwell CNC heads topped by the Holley Lo-Ram intake. 

The turbo also was upgraded to a Pulsar G42 1450, and the VY LS ECU was ditched for one of Haltech’s new Nexus Rebel LS units. “That’s an amazing product; I can’t speak highly enough of it,” says Ross.

While everything was apart, the 4L60 was swapped out for an ATS Automatics-built Powerglide. Surprisingly, the rear end is still the factory IRS, with Import Drag Solutions coil-overs.

The LS3 made a comfortable 770hp to the hubs on 12psi with E85, and to date, the Supra has run a 9.75@143mph best. “That’ll be the goal at Drag Challenge; to run nines – and, obviously, finish!” Ross laughs. “I know I’m in for it with this event, but after following Hot Rod Drag Week and Sick Week in the States, I can’t bloody wait for it.”

Ross will be taking on the Hare & Forbes Machineryhouse Dial Your Own class at Drag Challenge 2024, 30 October to 3 November.

ROSS HARRIS
1986 TOYOTA SUPRA MK3

THANKS
JPA Performance; Matt Robinson; Haltune Performance Cranbourne; ATS Automatics; Import Drag Solutions, USA; Tony Webb; Marcus Hamilton; Performance Exhaust Echuca; Automation and Robot Services; Heathcote Park Raceway.