When it comes to cars, Junya Watanabe is a hard man to please. Despite owning a Lexus LS460 as a daily driver, the owner of Rocky Auto has little interest in modern cars. For him, the act of driving should be a sensual experience, from the moment you look at the car to the first time you turn the key and step on the gas pedal. Design-wise, as he puts it, there is nothing out there lately that has anything over vintage cars, an opinion that becomes obvious once you take a walk through his impressive shop, where close to 100 classics sit in various state of tune. However, Watanabe is also a realist—for as much as he loves older machinery, he isn’t really thrilled about their mechanical shortcomings, be it in reliability, surpassed technology or outright lack of power and safety. By mating the new with the old, Watanabe has made a name for himself and every time we stop by to see what crazy project is on deck, he pulls out something that blows us away.
Sourced from the US, this Datsun 240Z is one of the cleanest cars Rocky Auto has built, and they’ve done plenty in the past. You won’t find any carbon-fiber or other lightweight body parts; the whole idea was to go for a close to factory look, highlighted with a set of Panasport Racing wheels against the very ‘70s-like factory mustard yellow. Vitaloni side mirrors and an extended chin spoiler are add-ons that spice up the looks, much like the pinstripe running the length of the car. If it weren’t for a little V8 badge on the front fenders nobody would’ve ever guessed that this American import is packing an all-new heart. Forget your L24 or stroked L28 straight sixes, Watanabe wanted to extend the American connection all the way to the engine bay, in which a Chevy LT1 now resides. The 5.7L single overhead cam almost looks small in the spacious S30 engine bay, yet it’s been fitted as far back as possible against the firewall to provide more balanced weight distribution. The engine was sourced from a ‘93 Pontiac Trans Am and chosen for its smooth drivability, low-end torque and of course, for that unmistakable V8 sound. A custom stainless steel exhaust was fabricated to highlight the offbeat rumble and ends in a polished single tip, replacing the original twin pipe silencer. With so much space to play around with there was enough room to place a large K&N cone filter right behind the grill where it can get as much cool air as it would ever need. The LT1 was stripped of all its plastic covers and every exposed aluminum part was polished to a mirror shine. Edelbrock valve covers were then installed for a more vintage feel along with a polished oil cap.
With more weight over the front wheels there was no way Watanabe would want to struggle with turning the steering wheel at low speeds, so on went an electric power steering system, making parking maneuvers a breeze. Although the modifications are light, the single cam LT1 develops around 300hp, up 25 from its stock 275hp rating. It might not be much to write home about but with the 240Z hitting the scales at around 1,000kg (approximately 2,200lbs) in full trim, you will be surprised at how fast this thing moves off the line. Larger capacity V8s always serve up bucket-fulls of torque, and with 45kg-m (325lb-ft) on tap, you can literally drive the car around all day in third gear! Plant your foot in any gear and it will take off with an accompanying concerto of pushrod mayhem and exhaust fury. Sending drive to the rear wheels is a Corvette T56 6-speed transmission, offering a nice spread of ratios including a very tall 6th, perfect for cruising around in.
With newfound performance and weight increase over the front wheels, the suspension needed to be modified. Specially tuned Rocky Auto dampers went in along with lowering springs to help tighten up the feel of the car. This was built primarily as a comfortable street car so the dampers give a silkier, smooth ride. R32 Skyline brakes and rotors offer increased pedal feel and braking performance that the stock braking system could only dream of. The interior has been left stock, only retouched here and there with fresh leather for the seats, door panels and the shifter boot. A vintage Rocky Auto Z wood steering wheel and white-faced dials are the only items to have been upgraded since Watanabe prefers to keep things simple.
After swapping anything from RB25s/RB26s, SR20s and VQ35s into all sorts of Japanese classics, this S30 is a much welcomed breath of fresh air. It’s obviously not the first V8 transplanted into a Datsun 240Z, but done the Rocky Auto way it somehow has a uniqueness all its own.
Datsun 240Z (S30)
Hometown Okazaki City, Japan
Occupation Staying true to the old school
Power 300hp; 325lb-ft
Engine 5.7L GM LT1 motor; custom Rocky Auto engine mounts, intake pipe, electric power steering, stainless exhaust system and racing radiator; K&N cone filter; Edelbrock valve covers
Drivetrain Corvette T56 6-speed manual transmission
Footwork & Chassis Rocky Auto suspension kit
Brakes Nissan R32 Skyline calipers and rotors
Wheels & Tires 15x7" Panasport Racing wheels; 205/60R15 Bridgestone Potenza RE-01 tires
Exterior Vitaloni side mirrors; HID headlight conversion
Interior Rocky Auto vintage wood steering wheel and white-face MPH gauge kit