When you spend 31 years racing the same car, you amass a knowledge base on that car like no one else. You know every nut and bolt-which ones will strip if you turn them 1/4-turn more, and every specialty fastener-and you know what works and what doesn't. Just like being married for more than a decade, you also know every blemish on your love, and have learned to overlook them. You've shared some of your best and worst life experiences together, and you know that there's more to your relationship than show-quality paint.
Keith Seymore has been racing this '74 Chevelle for 31 years, and his history with the car extends longer than that. His dad worked for General Motors for 35 years. One of the long-standing traditions of working at a Detroit automaker was ordering your new car every few years. Even to this day, people who really care about cars take special care to custom order their car exactly the way they want them. And if you can, you call in favors to make things happen that aren't on the options list. That's how you find cars decades later that defy what order books say was possible for that year-muscle car collectors have dreams about these sorts of things. When it came time to order a '74-model GM car for Keith's mom, his dad wanted a two-door Chevelle, but he wanted to add the police package goodies. He also wanted the opera window, which turned out to be the biggest challenge of the custom order. After working with the car order desk for weeks, they finally gave him the phone number of the plant manager and said to work it out with him. So he did.
Keith's mom drove the Malibu for four years, and then it was on to the next new GM car. And the Chevelle with the cop motor, cop suspension, and cop shocks was offered up as Keith's car to drive. In stock form, the car was pretty impressive, especially for a mid-'70s commuter. Even though the engine from the era of detuned V-8s, it was still a 454. The police package gave it the LS4 version of the big-block, which had a rating of 235 hp, an aluminum intake, and Q-jet four-barrel. The TH400 transmission had a performance valvebody, and the 10-bolt came with 3.42 gears and a posi. Eight-inch Corvette Rally wheels were also part of the deal, wrapped in HR60-15 Goodyear blue dot pursuit tires. Heavy-duty suspension and skid plates, beefy sway bars, and a gauge cluster that included a tachometer and actual gauges were also thrown in. One of the more interesting items was a performance console transmission shifter.
It didn't take long for Keith to find himself and the Chevelle at Lapeer Dragway, a local dragstrip that a lot of Detroiters make use of. The car in stock, 4,100-pound form turned a 15.10 the first time down the dragstrip. By the end of the day, Keith had quickened that to consistent 14.90s. And that was the start of a 31-year racing relationship with the car, and the start of a refinement process that continues today.
With a 4,100-pound car, there's a lot of weight to shed. Low-hanging fruit included the steel hood and the 60-pound front bumper. And behind the front and rear bumpers was reinforcement and miscellaneous fat that was worth about 50 pounds on each end. As Keith's relationship with the car lengthened, he got more and more refined in his weight-reduction tactics. He found that a 12-gallon gas tank from a Chevette would fit between the rear framerails, retaining a factory look and avoiding the need for a fuel cell. He started moving weight from the front to the rear, such as the battery. A two-core radiator holds less coolant than a four-core, therefore weighing less. And by some miracle, the car cools fine with a two-core radiator.
Weight reduction only goes so far, though. So the quest for more power began. Keith knew he would regret making changes to the car that would prevent it from being returned to stock if he ever decided to do so. Instead of tearing apart the original 454, he yanked it out and stuck it in the corner. He started on what would be a line of six big-blocks. The first couple were pretty mild steps up: A 482 and 462, based on production blocks. Then a 510 was built that launched Keith on a serious cubic-inch fetish. Next came a 572 and then a monster 624. That block cracked between the bores, ending that engine's stint in the car. While the 672 was out and the 555 was being built, Keith tossed the original 454 back in the car under the premise of keeping the trans and rearend lubed and healthy. Naturally, he worked a few races into that maintenance schedule. To show just how much a few hundred pounds of weight reduction and some precise chassis tuning and weight reduction is worth, the car turned a 12.25 e.t. with the original 235-horse engine in it. We have to tell you, we'd be embarrassed to get spanked by a boat with a smog motor in it!
The 555 that's currently in the car stepped things up quite a bit. Scott Williams at S&K Racing built the engine to make the most of the way Keith had his Chevelle setup. The engine uses Weisco 13:1 pistons with AFR heads and a Cam Motion bumpstick. Lukovich Racing handled all of the machining work on the Bow Tie block, K1 Technologies crank, and rods. A lot of the efficiencies in transferring that power to the ground come through the original TH400 transmission that was reworked by Jim Paquet of JPT. The gearbox uses a standard pattern, full-manual valvebody. This provides high-quality shifts on demand, but lets Keith retain the original shifter. The car has turned a best quarter-mile time of 10.001 at 136 mph with this powertrain combination.
The exterior's great looks are more accidental than intentional. The car has never been painted all at once. In fact, the roof and upper quarter-panels still wear the original black paint. Since the car was a daily driver for many years, the doors and rear-wheel openings rusted out at different times. The doors were replaced and patch panels welded in, and sections of the car were painted as needed.
Even though the car is 36 years old, it never reached the level of decay and decline that most old cars do. Accordingly, the interior is mostly original. The seats are original and the front buckets have been recovered once in the original material. Keith ditched the swivel feature of the seats for more weight savings. The Rally gauge cluster that came with the police package is still mostly there and functioning. The tachometer died, and Keith couldn't find anyone who could fix it. But he noticed that an '87 IROC Camaro tachometer was about the same size and had the same sweep, so he swapped the guts to use the IROC tach with his original gauge face. Similarly, the clock croaked, and he swapped in an oil pressure gauge from an '80s GM diesel truck. There are few things in the interior that you don't see. Inside the center console is an MSD ignition retard control. Behind the glovebox door is the MSD 6AL box where Keith can plug in rpm-limiter chips. Flipping down the ashtray reveals a start button. The original rear-window defogger switch now turns the Holley electric fuel pump on and off. These are the type of cool and thoughtful details that set Keith's car apart from stripped-down race cars.
Keith's racing affair with this '74 Chevelle was incremental for many years. In the mid '90s, he was playing around with the rear suspension and the attachment points in particular. He drilled some extra holes for upper control arm mounts and ended up breaking the frame. At that point, he and his dad-who worked with him on the car throughout-decided that they needed to take the body off the frame. They ended up narrowing the rear framerails of the car 11/4 inches on each side and re-engineering the suspension mounts. To narrow the framerails, the rear crossmember was sectioned and the factory rails were simply moved closer together. That change allowed him to fit a 131/2-inch tire on a 10-inch wheel without modifying the factory wheel tubs. The new locations for the trailing arms allowed Keith to achieve a better instant center, delivering race-car four-link geometry with factory parts.
The only question at this point is, what's next? Keith has had quite a bit of success in the NMCA racing series, racking up wins from 2001 to 2008. He's thinking he might have a good recipe to compete in the Factory Appearing Stock Tire (F.A.S.T.) racing series. Just like any good relationship, time is well spent embarking on the next step in the adventure.
'74 Chevy Chevelle
Keith Seymore • Troy, MI
Total cost to build: $15,000
Type: Chevy 555 big-block
Block: GM Performance Parts Bow Tie short-deck CNC
Oiling: Moroso wet sump
Rotating assembly: K1 Technologies 4.250-inch forged crank and H-beam rods; forged 13:1 Weisco pistons
Cylinder heads: AFR CNC aluminum castings with 118cc chambers and 2.30/1.88-inch valves
Camshaft: Cam Motion 284/297 at 0.050, 0.798/0.764-inch lift
Valvetrain: COMP Cams stainless 1.7:1 rockers; PSE springs, COMP Cams retainers and pushrods
Induction: Dart 4500-series intake manifold ported by CFE, Holley 950-cfm for NMCA racing, and 1050 Dominator for bracket racing
Exhaust: Modified Hooker 2 1/4-inch headers with 4-inch collectors, dual 4-inch Flowmaster mufflers
Power adder: none
Fuel system: Holley mechanical fuel pump at the engine, Holley electric pump at the tank
Ignition: MSD 6AL, distributor, coil, and plug wires
Cooling: Two-core replacement radiator, mechanical fan, aluminum water pump
Output: (estimated) 900 hp at 7,000 rpm and 900 lb-ft at 4,500 rpm
Built by: Scott Williams at S&K Racing
Transmission: GM TH400 auto with full-manual valvebody built by Jim Paquet of JPT, Coan 9-inch 4,000-stall converter, factory console shifter
Rear axle: stock 8.5-inch 10-bolt rearend housing with 4.10:1 gears, Mark Williams axles, C-clip eliminator kit and spool
Front suspension: factory control arms, 90/10 drag shocks, travel limiters
Rear suspension: station wagon passenger-side leaf spring, stock shocks, driver-side spring, and boxed factory control arms
Brakes: factory front disc and rear drum brakes
Wheels & Tires
Wheels: Corvette Rally wheels 15x6, front; 15x10, rear for street (15x8 for racing)
Tires: 235/70R15 Firestone, front; Mickey Thompson 29.5x13.5x15 ET Street (29.5x10.50x15 slick for racing), rear