Building the Ultimate Street 510
Words/Photos by John Roper
Kevin Koford has been into Datsuns since the early days of the scene, dating back as far a 1977. Even though all his high school buddies lusted after the ubiquitous muscle cars of the era, he pined for something a little different. That "unusual" car came along in the form of a Datsun 510, after one of his schoolmates showed up one day with a bright orange wagon. Lowered on some 13x7 AREs, it hooked him immediately. A few weeks later he found his dream realized when he picked up a similar orange wagon off a used car dealer's lot. These little Japanese tin boxes can be very addicting, and this car would only be the beginning.
After his salad days of Datsun-dom concluded, Kevin settled down, bought a "normal" car and moved on. But he always kept in the back of his mind what he would do if he ever built another 510. Fast forward to 1998 when Kevin finally knuckled down and bought another 510, the one you see here. Although bone stock at the time, from day one many grandiose plans were being constructed for it.
He removed the stock engine and starting making plans to build the infamous 2.2L stroker version of the stock type engine, known as the LZ22. During the research portion of the swap, Kevin found his way over to the shop of the great Steve Epperly. Those in the Datsun know will likely recognize that name, as he's had a hand in building a vast number of Pacific Northwest Datsuns. His shop, Z-Therapy, has also rebuilt hundreds of 240Z and 510 SU carburetors for many happy customers over the years. Steve made a few suggestions on what to do, but probably created more questions in Kevin's brain than answers. Keep in mind that during Kevin's hiatus from the 510 scene, things had exploded. People were doing things that no one in 1983 would have even dreamed of.
On the suggestion of another Oregon Datsun guru, Michael Spreadbury, Kevin started looking into swapping the KA24DE from an S13 240SX into his little Dime. This engine is becoming rather commonplace and inexpensive as copious amounts of S13/S14 owners switch to the powerhouse SR20DET. As such, they are being seen more often in 510s and Roadsters than in their original donor chassis. Although these engines get no respect from 240SX owners, they can really come alive when you swap them into a car that is nearly 1000 pounds lighter. And Kevin decided to up the ante even more with his.
As the swap commenced the decision was made to use forced induction to double the meager horsepower of the stock KA24DE. The engine blocked was bored .020 over in anticipation of custom made forged JE pistons. In addition to the full floating wrist pins, they were used to drop compression to a more boost friendly 8.0:1. With a stock forged crank and rods the bottom end of the KA24DE is quite stout from the factory, so these items were simply balanced for the rigors of high RPM use. The head retains its stock ports but benefits from the installation of JWT S-1 cams, JWT 8-way adjustable cam gears, new guides, and a 3-angle valve job.
Kevin ditched the factory exhaust manifold in favor of a custom tubular header fabricated by Steve Epperly, to send the exhaust gases either through the HKS 40mm wastegate, or into the custom Turbonetics T3/T4E turbo. When the intake charge is compressed, it is routed through stainless piping and into a Starion intercooler. After the boosted air is cooled off, it heads for either the HKS Type 1 blow-off valve or into the stock throttle body and intake manifold. Since the stock 270cc injectors quickly proved themselves to not be up to the task of all this power, they were replaced. A Walbro 255 LPH in-tank fuel pump now feeds high-octane fuel through braided stainless lines into Nismo 740cc injectors. To expel spent gases, a custom 3-inch ceramic-coated downpipe feeds the mandrel bent 3-inch exhaust system. Quieting this cacophony is the job of a stainless Borla XR-1 muffler. To send the power rearward, a JWT 11 pound aluminum flywheel and ACT clutch attach the engine to the stock S13 5 speed transmission.
With a JWT modified ECU, the combo proved very potent. It mainly excelled at showing Kevin how poorly the stock rear suspension handles this kind of torque. So he paid another visit to Epperly's shop to address the issue. On Steve's recommendation, the entire rear suspension (and part of the floor) was scrapped in favor of a one-off 4-link live axle set-up. Since the 510 wagon live axle is one of the stoutest third members Datsun ever built, it was called to duty for this application. To fit tires that were wide enough that they wouldn't just go up in smoke any time full throttle was applied, several changes were made. Steve took the wagon axle and swapped in a Nismo 3.89:1 LSD, S13 disc brakes, narrowed the axles and housing, and custom made a 1-inch sway bar. The final step in getting the 225/40-16 tires under the fenders without flares was to actually pull the entire quarter panel out approximately 1 inch. This modification is so amazingly subtle that unless parked next to a stock fendered 510, it is all but invisible.
Since nothing remained of the stock bits out back, those same stock underpinnings would not do up front either. As with most 510s, the front suspension is an amalgam of different JY Datsun parts. Starting with a modified '69 510 crossmember (it has slightly better geometry than the later units), Kevin added '79 810 strut housings and spindles. Using 280ZX hubs, he put together a combination of Stillen cross-drilled rotors meant for a Z31 300ZX, and massive Toyota 4Runner 4-piston calipers. To assist in adjusting ride height Coleman coil-over sleeves were used, and Eibach 2.5-inch springs got the nod to stiffen it all up.
Outside the car, modifications were kept to a minimum to retain the classic look of the little Yokohama shoebox. Other than the aforementioned pulled fenders, changes were limited to minor updates like the vintage BRE front "spook." To keep the intercooler out of the way of air coming directly through the custom aluminum radiator, the Starion 'cooler was mounted between the bumper and the spook. As low as the car is, you barely even notice it unless the car is coming up hard in your rearview mirror. The front and rear lights were replaced with their Euro counterparts to help dress things up further. Kevin also replaced the stock Datsun fender badges with brand new JDM Bluebird badges. To continue the trend, a rare JDM Bluebird grill and SSS grill emblem were also purchased. To keep it subdued, the 510 was repainted the original Code #019 Sunshine Yellow.
While the car was driven in this configuration for quite some time, bringing both smiles and accolades to Kevin, he longed for more. The JWT-modified ECU was able to make the car produce over 200hp at the rear wheels, but Kevin knew this was the limiting factor. He placed to the good folks at AEM for one of their stand-alone EFI systems. A visit to John Reed at RRev Motorsports had him on his way to being able to tune this beast to it's full potential. At the time of this writing, nothing more than a baseline tune and 6psi has created more power than the old set-up. With some extensive dyno tuning, and a streetable 16psi, Kevin and the crew at RRev are confident that 300-330hp at the wheels is not only possible, but very likely. While it was not built to be a show car, it has won its fair share of trophies, generally taking Best of Show everywhere it goes. But Kevin hasn't forgotten what he built this car for, to have a lot of fun on the street.
Not to pull back the curtain too far, but we often run into snags on these types of photo shoots. Anything ranging from inquisitive onlookers, to the full court press is possible when out in the field. This time was no exception. While I was hanging out of the window of a rental car snapping some rolling shots of Kevin's yellow dime, we were both pulled over by Portland PD's finest, on our very first pass. Convinced we were up to no good, she told us in no uncertain terms that we would have to leave town or be arrested for street racing! Which is odd, since we were only going 30mph in a 35mph zone. At least she was really, really hot.
Kevin Koford has good reason to be proud of what he has created. As with most project cars, it's never really finished. He has plans for future upgrades, and if he stays true to form they will be both tasteful and powerful. As they used to say in the adverts from the 70s, "Drive A Datsun, Then Decide."