THE Sigma Scorpion was Mitsubishi’s affordable sports coupe for the 1980s, although we use the term ‘sports’ pretty loosely. Powered by a 2.6-litre four-cylinder producing a monstrous 78kW, it barely had enough grunt to get out of its own way – it was a sports car for your grandma. But with a fairly large engine bay and solid rear axle, it makes the perfect blank canvas for a sleeper build, which is exactly what Vince Riccotti and Jason Ghiller from Tunnel Vision have done.

A couple of years ago Jason had a 3.0-litre Nissan VG30 motor from a 300ZX sitting at his workshop that he planned to put in his work ute. But one day he and Vince were browsing Gumtree and came across this mint, grandma-spec, one-owner Scorpion. They bought the car that day and had the V6 sitting in the engine bay that night.

From there Vince and Jason built the motor up with forged conrods and SPS pistons, massaged the heads, and Jason made up a custom plenum and exhaust manifold for a single Garrett GT42 turbo.

While the VG30 isn’t a really popular engine, it’s a seriously trick bit of gear that powered Nissan race cars to three IMSA GT Championship titles in a row. It uses an iron block with a big single-piece crank girdle similar to the RB series, and dual-overhead-cam alloy heads. And for a 3.0-litre DOHC V6 it’s very compact, which makes it great for an engine swap.

Backing the V6 is a two-speed Powerglide and nine-inch rear end, while engine management is through a Haltech Platinum Series ECU. While the car has never been on a dyno or quarter-mile drag strip, Vince is confident it would run a low 10 or high nine-second quarter-mile. With all the factory trim and stock wheels, it’s more of a quick street car than anything else, and Vince gets it out anytime he can.

We recently caught up with Vince at King Of The Street, where he was racing the car for the first time over the eighth-mile. Unfortunately the old Platinum Sport ECU doesn’t have a bump box feature, so the Scorp wasn’t really competitive in the heads-up racing and got knocked out in the first round, but it was still a fun day!

VINCE RICCOTTI & JASON GHILLER
1981 MITSUBISHI SIGMA SCORPION

Paint: Red

ENGINE
Brand: Nissan VG30 3.0L V6
Induction: Custom manifold
Cams: Custom-grind
Heads: Ported factory
Rods: Eagle H-beam
Pistons: SPS
ECU: Haltech Platinum
Turbo: Garrett GT42

TRANSMISSION
Gearbox: Powerglide
Converter: 3300rpm stall
Diff: 9in, 31-spline, 3.5:1 gears

SUSPENSION
Front: Standard
Rear: Standard

BRAKES
Front: Standard
Rear: Standard

WHEELS & TYRES
Wheels: Standard GSR 15×7 (f & r)
Tyres: Standard (f), M/T ET Street 255/60R15 (r)