In resto-modding a classic, striking the right balance can be a difficult thing to achieve. Swing too far into the modifying realm and you risk completely destroying a car's identity; but get it right and the result can be spectacular. If you want proof of the latter, you'll definitely find it in this RB30 swapped '74 Datsun 240K GT C100 from New Zealand.
Before we talk about owner Leighton Hamlin and delve into his seven-year quest to turn a neglected Kenmeri into the show- and street-stopping machine it is today, it's worth explaining how it came to be and why we're not calling it a Nissan. Yes, it's a C110 that was originally assembled in Japan to the same basic spec as the second-generation JDM Skyline. However, it's also one of a small number of examples that was sold in New Zealand between 1973 and 1975—albeit badged as a Datsun. The 240K moniker reflected its export-spec L24 engine.
From the moment Leighton got his hands on the rare two-door hardtop coupe 10 years ago, he set in motion a plan to rebuild the car with a modern twist—something that perfectly balanced both restraint and excess. "My friends and I always talked about whether we would rather have a car that looked average but was fast, or a car that looked awesome but had no power," Leighton explained. "I thought, 'Why not have both!'"
Knowing it wasn't going to be a small task, he did his homework before any repairs or modifications were made. An L28 and five-speed manual gearbox, along with a bunch of other parts from a rusted-out donor car provided a starting point, but the more he thought about what he wanted to achieve, the more grand his plans became.
Leighton also had clear intentions for the bodywork and interior, and they largely revolved around a less-is-more approach. Messing with the C110's iconic early '70s Japanese lines was never an option. But through a few custom changes to the exterior coupled with a drop and a set of perfectly fitted wheels, it's taken on a whole new level of aggression. We could talk about the custom Koni shocks and Cobra springs that set the chassis 1.5 inches lower or the deep gloss Ford Midnight Black paint, but it's the metalwork that's really pulled together all these upgrades. In the age of FRP, it's refreshing to see some good ol'-fashioned fabrication, and Middleton Panelbeaters have done an exceptional job blending the handformed steel flares to the fenders and scratch-building a steel front splitter and trunk lip.
According to Leighton, the smallest details provided some of the biggest headaches for the exterior. A missing GT badge, for instance, took six months to track down—and in Kuwait of all places. A replacement stainless steel surround for above the windscreen had to be adapted to fit from an Australian Ford Falcon XY item after a fruitless worldwide search for an original. It's all part of the challenge of a restomod, though.
Inside, only a few select upgrades were deemed necessary, and after the front seats were re-bolstered to their original shape, TLC is all that was required to bring the rest of the retrofitted C110 interior trim back to life. An old-school Nissan wood-rimmed steering wheel was also added. The Datsun's factory-spec dash instruments remain, but they've been recalibrated to suit what's going on under the hood—a place where things get both interesting and a little crazy!
In the quest for horsepower, there were a number of modern routes Leighton could have taken, but in sticking with the Nissan family, an RB inline-six won out. But even if you've stared over the shaved, wire-tucked and intricately detailed bay for hours, the centerpiece is probably not what you think it is. Well, not entirely anyway.
Through the mid-'80s and early '90s, GM's Australian branch, Holden, turned to Nissan for a 3.0-liter engine to breathe some emission efficiency into its line of Commodore-badged cars and wagons—a request that was answered with the 2,962cc RB30. The Nissan-powered Holden variants are long obsolete now, but in this corner of the world their engines live on in builds just like this one. The largest RB derivative is a tough motor in stock spec, but throw in a set of forged CP slugs and Carrillo rods as has been done here, and you've got yourself an engine base that's primed for insane power.
Although the RB30 was offered in a turbo specification (RB30ET), in any of its forms a twin cam cylinder head was not. It's a bolt-on retrofit, though, and the reason why there's an RB26 DOHC 24-valve upgrade here. But like the block, the head is not stock either, and on top of some extensive port work, it's been fitted out with an HKS Step 2 cam kit and 1mm oversized intake valves wrapped in heavy-duty valve springs.
Increased strength and flow had been the priority with the engine build, and it was all in aid of the real power-making piece in this puzzle—that Garrett T72 turbocharger perched high on a custom manifold. As inconspicuous as it might be from the outside, there's a large custom front-mounted intercooler in the mix, too. From the turbo back, a full 3-inch exhaust system features handmade mufflers.
Boost—a healthy 25psi dose of the stuff at full tilt—is controlled through a Turbosmart wastegate and delivered into the cylinders through an R.I.P.S front-facing plenum chamber equipped with a large 90mm throttle body. With an appetite like that, Leighton ensured the RB30's thirst was well quenched when it came to fuelling. There's a Carter lift pump, custom surge tank and twin Bosch pumps in the trunk, plus an HKS rail and big injectors at the business end.
A Link Xtreme G4 engine management system gives the RB30DET its firing orders, with subsequent dyno tuning at HiTech Motorsport revealing 456whp, at a howling 6,000rpm. In a chassis that doesn't weigh much more than 2,500 pounds, it's enough to set the tires spinning through third gear like it ain't a thing.
The original five-speed gearbox Leighton installed with the L28 is long gone now. In its place is a series-two RB25DET tranny that runs through an Exedy clutch. Further upgrades were made in the driveline with a custom driveshaft and an R200 long-nose limited-slip rear end.
Given the car's substantial increase in performance, a major upgrade in the brake department became a necessity if Leighton was to put the car back on the road, legally. This sort of thing isn't much of a problem in New Zealand as long as certification guidelines for a modified vehicle are followed. "It took a bit of research, but I found a disc brake conversion from the States for a 240Z," Leighton says. "Both the S30 and the C110 share the same hubs, so I knew I could make it work—which it did after we fabricated some caliper mounts." The kit includes four-piston calipers with 11.8-inch cross-drilled rotors for the front while dual-piston calipers and slightly smaller 10.6-inch rotors make up the rear.
As it stands now, there are only a few small things left to finish. After replacing more universal joints than he cares to remember, a switch to CV halfshafts will be happening very soon, meaning more boost can be added. However, high or low boost, it doesn't really matter to Leighton because the result of this decade-long dream is much more than dyno numbers and outright acceleration. It's about the happiness a car built with passion can bring. "It's just so rewarding," Leighton says. "I could be having the worst day, but just getting into the car and going for a drive instantly makes me feel good. That has to be the coolest thing about it."