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Article by Mark Warner
Photos by John Roper
Kevin Koford’s Datsun 510 is anything but ordinary. His passion for 510s is also remarkable, starting many years ago in high school, back when he bought his first dime—an orange 1972 wagon—and immediately set out to modify it. A succession of 510’s followed, and the more Kevin tinkered with them, the more he learned. But some of the lesson were difficult ones to digest, such as the time he pulled the valve cover on his ’72 two door.
“I started tinkering with the engine,” Kevin says, “not knowing much about Datsuns or how the engine worked. I took off the cam sprocket and somehow got it back on without using the essential wooden block to keep the chain from falling into the crankcase and keep the tensioner in place.”
When Kevin went to start the engine, pistons hit valves and the engine was ruined. Then the financial reality of the situation set in when Kevin called the local Datsun dealership to price a rebuild. “They said $900, which I could not afford at the time. So I bought a shop manual instead and figured that I would teach myself how to do it.”
Since that day, Kevin has never looked back, learning a great deal about cars and having fun along the way. “I enjoyed knowing more about engines and cars than my friends. I absorbed all I could by hanging out with fellow enthusiasts and subscribing to every car magazine that I could get my hands on.” By the end of high school, Kevin was one of the “go to” guys for modifications and most things car related.
Kevin went through several more 510s and a muscle car before heading off to college, where he took a detour into the world of stroked Volkswagen Rabbits. Fast forward to 1998. Kevin was now married and gainfully employed. More importantly, the Datsun bug had never really left him and he was in a financial position to build another 510 “the right way.”
“My wife had no clue what a 510 was,” Kevin says, “but she agreed to go along with the idea.”
Kevin narrowed his searched for a 1973 two-door model, with the quest leading him to a fairly clean project vehicle in his hometown that had original paint and some “questionable” modifications. It also had a 5-speed, an L20b, and dual SU carburetors. The owner also tossed in reams of reading material and enough boxes of spare parts to fill up Kevin’s Toyota 4Runner. One of those spares was a JDM EFI intake manifold.
“I thought that sounded like a great idea, so I got a hold of some shop manuals and taught myself about the batch fire EFI of the second-generation 200SX’s.”
The manifold needed to be modified, however, and Kevin eventually found himself at Steve Epperly’s shop in Salem, Oregon. Little did he know that Steve would become a major influence on the project.
“[At Steve’s shop] I saw how far 510’s had evolved since I had sold my last one in 1983,” Kevin says. “Steve had just finished building Michael Spreadbury’s 1970 VG30ET powered ‘Strutless Wonder’ 2-door and I was totally blown away.”
Kevin started hanging out the shop to learn as much as he could. During one of these visits, Spreadbury suggested that a KA24DE would make a nice addition to the engine bay in Kevin’s car.
“I did some research and determined that it would be a great engine for the car. It had sequential EFI, a DOHC cylinder head, and 2400 cc of displacement.”
Steve then further suggested that the KA engine would be easy to turbocharge. One thing led to another and suddenly a monster engine was in the works.
“I decided to build it the right way from the start, with forged pistons and all the pieces that would make it bulletproof.” Kevin even had Steve build a trick, one-off tubular exhaust manifold that “is a work of art.”
With major horsepower in store for the car, it was time to turn to the problem of putting all those ponies to the ground. Kevin and Steve decided that it made sense to replace the stock semi-trailing arm rear suspension with a live axle. The plan was to copy Steve’s killer B210 axle layout with its triangulated 4-link.
Out came the plasma cutter and suddenly the IRS and entire rear floor was gone. During the surgery, the fabricators also decided to make some serious upgrades to the front suspension. “I wanted something that would fit my newly acquired 16x7 Panasports within the stock wheel wells.”
The new rear end was constructed from a narrowed 510 wagon axle housing. The open diff was replaced with a NISMO LSD with 3.89 gears. 1989 240SX rear brakes and 1983 280ZX rotors round out the package.
The front suspension, although somewhat more conventional than the rear, was also a big project. It started with a 1969 crossmember that was cut, flipped and rewelded to fit the KA front sump engine. The struts were then sourced from a 1979 810 and were shortened to accommodate 1988 MR-2 Tokico Illumia rear strut inserts. The hubs were taken from a 1983 280ZX and the rotors were Stillen cross drilled and ventilated units from a Z31 300ZX non-turbo (4 lug). The calipers were sourced from a 1994 Toyota 4Runner and were fitted with the rotors via a custom machined spacer plate. Coleman’s coil-over collars and Eibach ERS springs completed the front suspension.
Under the hood, the solid 1992 240SX block was bored .020 over. The rods used were stock forged steel units modified with ARP bolts, bushed and honed for full floating pistons as well as polished and shot-peened to relieve stress. JE supplied the custom spec double Spiro loc 8.2:1 pistons. The entire rotating assembly was then balanced.
The head is surprisingly close to stock specs, with just new valves, 3 angle grind, and new guides, springs and seals. The camshafts used were Jim Wolf Technology “Turbo” units. Hooking all this potential power up to the stock KA transmission is an ACT heavy-duty extreme pressure plate with an ACT high performance street disc. The flywheel is a JWT 11lb. aluminum unit.
The fuel injection was another major project, as Kevin knew little about the KA system when he started. Thanks to great factory shop manuals, however, as well as a lot of research and the help of friend Jody Donker (who works for Toyota as a Field Technical Specialist) “it now all makes perfect sense.”
The electrical harness was modified by Kevin utilizing a giant enlargement of the 240SX ECCS schematic. Steve and Kevin fabricated the stock-appearing fuel rail which houses 740cc NISMO injectors and connects to the braided fuel system lines. Feeding the large injectors is a Walbro 255 lph pump in a custom-made 300ZX TT housing. The fuel tank was fabricated by Steve’s father, Al.
The ECU was then programmed by Clark Steppler at JWT and after some time on the dyno, was further enhanced with an APEXi Super AFC-II to assist with the fuel curve.
The entire fabrication effort took nearly 5 years of Sundays and various days off to complete. Many things were tried and discarded or modified in the quest for Kevin’s definition of the ultimate 510. The end results speak for themselves, with everything meeting or exceeding expectations. “The live axle works very well and is completely hidden to the casual observer. Even the bodywork is all steel except the front spoiler.”
At its first outing at the Canby All Datsun Show in June of 2005, Kevin’s car took home Best Paint, Best Engine and Best 510 (4 Cylinder). He then took it to Shasta in July of that same year.
“I was not expecting much at Shasta, due to the proliferation of SR20 powered cars and the way that everyone believes that they are the future of 510s.” You can imagine Kevin’s surprise when he took home 2nd Place 4 cylinder 510 as well as the Best Overall 510 award.
Despite these show wins, Kevin insists that the car was not built to be a trophy car. “It’s a fun street vehicle. I had to re-learn a lot about 510’s as well as what has changed in the Datsun world since I sold my last 510 back in 1983. Steve and his dad taught me how to fabricate, weld and machine what was not available and make things work that others said wouldn’t. Without their advice and help, this car would not be what it is today.”
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