Insane V8-powered Suzuki Mighty Boy

How do you impress people with a Suzuki Mighty Boy? It sure helps if you stuff an angry LS in it!

Photographers: Jordan Leist

A Mighty Boy has been crowned Motorvation Grand Champ. There’s a sentence I never thought I’d ever be writing, but that was the big news earlier in the year when Simon Birch’s Battleship Grey Suzuki wowed everyone at Motorvation 36.

First published in the July 2022 issue of Street Machine

There were plenty of puzzled looks, slack jaws and shaking heads – mine included – when the car was unveiled at Motorvation and everyone realised they were looking at a Suzuki Mighty Boy, of all things. Once that initial shock wore off though, people started to really appreciate the amount of time and effort that had gone into the car.

What possessed Simon to build such a thing? “I set out to build a $20,000 skid car and failed miserably,” he jokes.

Simon’s sense of humour about the car becomes especially apparent when he shows me his entry form for Motorvation. The first question is, “Sum up your build here for us.” To which Simon had replied: “Hard to explain, but here goes. It’s completely built at home by someone with no idea and is real dardy-like. It incorporates a lot of stupid ideas that have been slapped together over a very long time.”

His response to the question about visual and engine modifications is even better: “It’s got shiny primer, an engine that sneaks out the bonnet and a body that stands up by remote, exposing the agricultural chassis and rattle-canned driveline. The 500cc three-cylinder and three-speed are tastefully dressed up to look like an L98 and TH400, and it’s controlled by a Holley carburettor ECU thingy.”

Sure, this isn’t the first time someone has shoved a V8 into a Mighty Boy, but that hardly explains the extent of what Simon has done to the demure Japanese hauler. There’s a full custom chassis that he fabricated at home, which houses the L98, Rossler Turbo 400 trans and very narrow nine-inch, and to make servicing the driveline easier, Simon thought it would be a good idea to make the front of the car flip forward and the body tilt up.

It’s really quite an ingenious design, especially the flip-front, as you can still lift the bonnet as normal if required. The body is hinged at the rear and lifts up using electric linear actuators, but first Simon has to disconnect the steering column and unplug a couple of connectors in the wiring harness, which only takes a few seconds.

While Simon might joke about the agricultural nature of the whole thing, it’s really quite nicely detailed, with nothing out of place. A lot of thought has clearly gone into it. The main reason behind the custom chassis was so that he could mount the engine quite far back, in order to make room for a radiator at the front without it sticking out under the bumper. This allowed Simon to fit a VY rad and thermo fans no problem at all.

The engine has been given a pretty decent going-over, with the heads ported and decked by Luigi’s Head Shop. “He decked them 25thou and then recessed the valves up 25thou to help with piston-to-valve clearance, but I had to fly-cut the pistons anyway because of the thicker valves,” Simon explains. The heads are topped with some neat finned rocker covers for just a touch of old-school cool.

One spot Simon didn’t skimp on was the intake. He went for a Holley dual-plenum item with twin 90mm throttlebodies, which are controlled by a Holley Terminator X Max ECU. It’s also got a mighty cranky cam in the form of a GM Motorsport Turbo Killer II stick. It’s got 237/243 duration @.050 and 0.620/0.623 lift, and it sounds like it. It’s definitely one of the best-sounding LS combos I’ve ever heard, and with 460hp at the hubs, it’s no slouch in the performance department, either.

Given that the car was originally built for doing skids, it’s got 3.25 gears in the nine-inch, which has been treated to 35-spline internals with a full spool. Combined with the Rossler Terminator 3 trans, it’s a pretty bulletproof driveline.

The front end was also replaced with a Mustang II IFS purchased off eBay, which then had nine inches cut out of the middle of it. It came with brakes that Simon describes as “shit flower petals”. And the rear brakes? “None yet, but I will hopefully be able to afford brakes all ’round soon.”

A ton of bodywork went into the ‘Zuki as well. On top of all the usual repairs an almost 40-year-old car requires, Simon added a completely new floor, firewall and transmission tunnel. The cargo area now houses massive tubs and a sizeable fuel cell, as well as the trans cooler.

The tailgate now has the number plate frenched into it, because Simon really wanted to run the pipes out of the recess where the plate was originally mounted. However, he was adamant about retaining the cargo rails that run along the bed and up over the roof: “They are such an identifying feature of the Mighty Boy; I had to keep them.”

While there’s not much of it, the interior of the little hauler is a highlight of the build, and since there was nowhere to hide anything, Simon decided to make a feature of all the bits that people tend to tuck away. “Hiding the wires in those tubes wasn’t easy. Firstly, making the tubes was a bitch to get right, and then making sure the right wires went in each one to where they needed to go and actually getting the buggers through there took ages,” he says. “After having the idea and mocking it up, I just had to do it, although there was more than one time I wanted to scrap the stupid idea. It’s my favourite part of the car now.”

Apart from some trim on the seats, the rest of the interior is either painted grey or satin black. The door trims and floor inserts are ABS plastic, so it’s a pretty low-maintenance cabin.

One part of the interior you may be scratching your head about is that large lever behind the shifter. It’s a Wilwood cutting brake, which has two 3/4in-bore master cylinders built into it. Pulling the lever activates one master cylinder; pushing it triggers the other.

As the Mighty Boy has such a short wheelbase, Simon was worried that he might get stuck going in one direction while doing a doughnut, which is why he went with the cutting brake. He wasn’t sure if it would work, but after some celebratory circle-work in the Motorvation Snakepit after being handed the Grand Champ award, it turned out the cutting brake worked mint – right up until it didn’t.

After exiting the Snakepit and idling down the return road, Simon discovered that his brakes weren’t working. Some quick thinking – plus quite a bit of yelling and swearing – saw him pick the gap between a couple of other Grand Champ contenders and a concrete wall, before sailing right over a four-foot limestone cliff! I can confirm that it was a rather hairy ride, as I was riding shotgun at the time!

“After we cleaned up all the brake fluid, I pulled apart the master cylinder and one of the seals had completely failed. I’d bought it a couple of years ago, and who knows how long it had been sitting on the shelf before that,” Simon explains. “Thankfully, there was very little damage – just a bit of paint off the crossmember and a dent in the headers from when it landed on the left front wheel and the suspension arm hit it.”

While the Mighty Boy might have turned out too nice to be a skid car, there’s no doubt we’ll see this little beast at many events in the future – along with plenty of slack jaws and WTF looks.


Paint: Battleship Grey
Type: L98
Inlet: Holley dual-plenum
Throttlebody: Twin 90mm
Heads: Ported and decked
Valves: Ferrea
Cam: GM Motorsport Turbo Killer II
Pistons: Fly-cut standard
Radiator: Fenix VY Commodore
Exhaust: Custom headers with MagnaFlow mufflers
ECU: Holley Terminator X Max
Gearbox: Rossler Terminator 3 Turbo 400
Converter: FTI 4000rpm stall
Diff: 9in, 35-spline, full spool, 3.25:1 gears
Front: Mustang II IFS kit
Rear: Four-link, QA1 coil-overs
Steering: Escort quick-rack
Brakes: Discs (f) with Wilwood cutting brake
Rims: JEGS Star; 15×4 (f), 15×10 (r)
Rubber: Federal Formoza 165/55R15 (f), Nankang NK Utility SP-7 295 (r)

All of these people played a huge part in the build and I couldn’t have done it without ’em: Jason Meldrum at SOS Fabrication; Matt at Stock to Shock; James at Proshine; Jeff Johnson; Clive at The Hammer Works; Nelg Taylor at Nelg’s Ali
Mods; KB Lock; Tyron Went; Jason Canvert; Michael Bowra; Clint James; Mike Roycroft.