Back in the glory days that nurtured the co-existence of the musclecar era and the National Hot Rod Association (NHRA), passionate Pontiac drag racers would look forward to every weekend that they would fight for the win (and hopefully divisional and national titles) in Stock Eliminator quarter-mile competitions.
Look around the NHRA’s Sportsman category Stock Eliminator classes today, however, and you’ll be hard-pressed to find many Pure Pontiacs remaining. Not so for 56-year-old NHRA driver Scott Burton, who has turned his Ram Air IV top-end ’701⁄2 Firebird into the fastest NHRA Stock Eliminator Pontiac in the country today.
“I’m a drag race junkie and like to run something other than a Chevy,” Burton says, repeating the familiar mantra chanted by Pontiac drag racers young and old. Last year, he ranked seventh in the nation amongst all Stock Eliminator drivers. This season he’s number four in the country in National Stock Eliminator points. (Scott’s son Brad’s E/SA ’72 455 HO Formula 455 was the 2010 NHRA Stock Eliminator National Champion, and the current NHRA Stock Eliminator points leader. The father-son team campaign their Pontiacs together.)
A power-to-weight ratio scale determines the NHRA’s Stock Eliminator classes. Burton explains: “Dividing the ’701⁄2 Formula’s 3,500-pound NHRA shipping weight by the Ram Air IV’s 370hp factory rating equals 9.46. Stock Eliminator classes are divided into ratio increments. That makes C/Stock (9.00-9.49) the natural classification for the car. NHRA rules allow a car to move to a faster class by legally removing weight. Since I wanted to run against traditional high-horsepower musclecars like Hemi Mopars and big-block Chevys, I decreased the Firebird’s weight to 3,315 pounds, which is the minimum for B/Stock (8.50-8.99).”
Scott Burton’s ’701⁄2 Firebird...
Scott Burton’s ’701⁄2 Firebird is a 10.17-second strip scorcher, the only Ram Air IV top-end Firebird competing in NHRA Stock Eliminator B/Stock class, and fourth in national points against all Stock Eliminator classes in this NHRA racing series.
Burton’s 408ci Pure Pontiac engine has clicked off a best e.t. of 10.17 seconds at 128 mph, and a 1.292-second 60-foot. Impressive? Yes, but even more so once you realize his Firebird adheres to the NHRA’s extremely strict series and class rules—after every pass the vehicle is weighed and fuel is checked, and the engine is subject to teardown at any time to verify compliance.
So how does Burton achieve his e.t’s under such tight rules and scrutiny? High Performance Pontiac checks in with him and asks him to reveal his combo secrets.
Due to the difficulty in sourcing useable castings, NHRA began allowing legal replacement blocks in Stock Eliminator classes in 2008. “You just can’t find stock-bore Ram Air IV blocks easily anymore,” Burton explains. That opened the opportunity to source a K&M Performance MR-1 cast-iron block with splayed four-bolt mains.
Verle Stevens in Denver did the machine work, including decking, line boring, boring to 4.185-inch, and honing with a block plate; adding lifter bushings; and deburring the block’s sharp edges. Piston-to-wall clearance is 0.005. The final displacement is 413 ci.
“My trick is to run 0.003 clearance on King main bearings and 0.025 clearance on Federal Mogul rod bearings. Proper bearing clearance is the key to bearing life,” he says.
NHRA Stock Eliminator rules dictate each engine run a stock-stroke crank (3.75-inches for the Pontiac 400). This Firebird uses a 400 “N” crank cast from ’71 production, although its original application is unknown. Burton had it magnafluxed, turned, and indexed; stroked by 0.013 (overstroking up to 0.015 is allowed); and its counterweights turned down in a lathe. The stroke is 3.763 inches.
Paired to the crank are Manley 4340 forged-steel connecting rods with a long 6.635-inch length (allowed in Stock Eliminator) and a 2.200-inch BBC rod journal. “The main reason for using the Chevy journal is the availability of better bearings,” Burton says.
Filling the cylinder bores are CP P1-CP NHRA-spec pistons with the stock 551-gram weight, valve reliefs, ring location, and ring grooves. Burton utilizes Total Seal’s 1.2mm C-33 chrome-nitrate face coating top ring with a gas-ported ring spacer, a cast-iron Napier second ring, and a low-drag oil ring. The piston/connecting rod assembly weighs 1,460 grams.
This Firebird is currently the only racecar with Ram Air IV heads (code-614) in modern NHRA Stock Eliminator competition. Head porting is strictly prohibited. Using bare, virgin castings, Burton measured a baseline of 225/140-cfm flow at 0.450-inch lift at 25 inches of pressure. Previous NHRA National Stock Eliminator champion Don Little of Westley, California, performed the head prep and assembly, including milling them to a 62cc combustion chamber per NHRA rules, and blocking off the heat crossover with aluminum. The heads produce an 11.55:1 compression ratio with 0.036-inch-thick Cometic head gaskets.
NHRA recently modified its rulebook to allow legal-replacement blocks, due to the scarcity of original, virgin castings. This 413ci Pure Pontiac engine is comprised of a MR1 cast-iron block, a ’70 Ram Air IV intake, and code-614 R/A-IV heads with absolutely, and we mean absolutely, no porting. What’s the contraption inline with the inlet radiator coolant hose? It’s another of Burton’s tricks—a one-way flapper valve, which allows him to quickly circulate ice water through the block to improve his engine’s performance in heads-up competition.
NHRA rules require stock valve diameters, which for the ’701⁄2 Ram Air IV are 2.11/1.77. Burton reveals his secret to obtaining better head flow without porting is to back-cut the intake valves 10-degrees and install them on a stock 30-degree seat. It increased intake flow 15-cfm over baseline. (The valves are Ferrea stainless steel.)
Comp 3⁄8-inch, 8.900-inch-length pushrods activate Harland Sharp 1.65:1-ratio roller rockers, which compress Manley Drag Race Triple valvesprings measuring 270-lb/in on the seat and 470-lb/in open.
The valvetrain is actuated by a Bullet hydraulic flat-tappet cam (268/272-degrees duration at 0.050, 110- degree LSA), which Burton advanced 2 degrees. He uses Shubeck ceramic puck lifters on the cam. Lift is 0.538/0.538 per NHRA rules.
Burton swears by his low-pressure Melling M-54D-S oil pump because it requires less horsepower to operate than a high-pressure pump. Another secret: He states the stock windage tray is prone to breakage and holds the oil too close to the crank. To replace it, he fabricated and installed a custom crank scraper, constructed from common 1⁄16-inch steel.
He also added extra baffling to a stock-replacement Moroso oil pan. “Upon hard launches, it prevents the oil from standing up in the back of the oil pan and getting into the rotation of the crankshaft and slowing it down,” he says. “Combined, the tricks are worth a 0.1 second.”
Burton has a secret for oil, too. “I run the engine on a steady diet of 0/10 weight Royal Purple, and change it every 50 to 70 runs. The light oils make the engine accelerate faster and the car go faster, probably 0.05 to 0.10-second,” he says.
Fuel, Intake, Carburetor, and Air Cleaner
The Firebird is outfitted with a 3.5-gallon fuel cell, ½-inch-diameter aluminum delivery and return lines, an Aeromotive A-2000 electric fuel pump with fuel return regulator, and an Aeromotive regulator set to 6.5 psi. His preferred fuel is 110-octane VP C-11.
A stock ’701⁄2 Ram Air IV intake (code 9799084) provides the platform for a 750-cfm Quadrajet, which was modified by Danny Ashley at Q-Jet Performance. What are its secrets? It has no primary metering rods, 0.061 jets in the primaries, and the secondary rods vary from 0.052 to 0.078 depending upon the altitude of the track. The carb is topped with a K&N base plate and 3-inch air cleaner, and two 1⁄8-inch phenolic spacer plates raise it off the intake.
Per NHRA rules, Stock Eliminator classes may use electronic ignition systems. This Firebird features an MSD Digital 6 control box and Pro-Billet distributor, Blaster 2 coil, Moroso 8mm wires, and Autolite AR72 plugs. Scott sets timing at 36 to 38 degrees, and the advance is locked out.
NHRA requires a stock radiator. Burton runs the lightest available, which is a two-core Firebird radiator. A stock water pump is no longer mandated in Stock Eliminator; he runs a Meziere electric unit and a Jegs 18-inch electric fan housed in a custom radiator surround.
Custom-made mild-steel headers step from 1.75-, to 1.875-, to 2.00-inch diameters into a merged 3.50-inch collector.
Transmission, Driveline, and RearEnd
NHRA allows Stock Eliminator racecars to run any factory transmission. Burton bolted up a modified Turbo 200 metric, featuring heat-treated internals, which was built by Scott McClay Engineering in Tehachapi, California.
“I like the trans because it weighs 95 pounds and has a smaller rotational mass than a Turbo 400 or 350,” he says. It’s mated to a TCI CCx 200-plus converter with a 5,800-rpm stall. He rows the gears with a Turbo Action shifter.
Connected to the trans’ output shaft is a custom 3.00-inch-diameter steel driveshaft from Front Range Driveline in Denver, featuring 1,350 yokes and U-joints.
NHRA Stock rules allow any corporate rear. Bolted underneath this Bird’s belly is a Chevy 12-bolt sourced from a station wagon because of its thicker axle tubes. It’s stuffed with a Mark Williams 35-spline aluminum spool, a Richmond Pro 4.56 gear, and 35-spline gun-drilled axles.
This steel bodied, super-powered Bird retains a factory dash, headliner, door panels, carpet, and seats (from a ’71 Firebird). Even the glass windshield and windows are retained, per NHRA Stock Eliminator series rules. A custom six-point chromoly rollbar (a four-point rollbar is required) and a five-point Impact camlock harness are safety mods.
Burton’s B/Stock Firebird retains stock upper and lower control arms, Moroso drag springs for a small-block Second-Gen Camaro with a full coil removed for correct ride height, Santuff double-adjustable shocks, and Del-a-lum bushings up front.
Out back, Caltracs split-monoleaf springs, and AFCO double-adjustable shocks provide the squat needed for launch. Weld-in connectors tie-in the subframe to the unibody.
“My trick is to set front-shock compression at four clicks from full tight and extension at fully soft for high-altitude tracks, and two-and-a-half turns from tight at a sea level track. For the rear, I set compression fully tight and extension two clicks from full loose.”
No sway bars are used, front or rear. NHRA requires all traction devices be bolt-on. In this Firebird, the traction bars are sourced from Phil Mandella Race Cars, and a wheelie bar was made by Ken Keir.
Brakes, wheels, and tires
Burton’s B/Stock Firebird...
Burton’s B/Stock Firebird roasts the hides of Goodyear 30x9 drag radials at the 2012 GTOAA International Convention Jim Wangers’ Private Invitational Drag Race in Denver.
In 2005, NHRA began allowing Stock Eliminator racers to bolt-on aftermarket brakes. Burton runs Wilwood’s Forged Dynalite Pro Series front brake kit with 10.75-inch rotors and four-piston calipers, Wilwood’s Dynalite Pro Series rear brake kit with 11.44-inch rotors and four-piston calipers, and a 11⁄16-bore Chrysler master cylinder from a mid-’70s Dodge Aspen. Weld Alumastars (15x3.5, 2.5-inch backspace front;15x10, 5-inch backspace rear) are shod in 27x4.5x15 Goodyear Front Runners and 30x9x15 Eagle Dragway Special radials. A 9-inch-wide back tire is the maximum size allowed, per series rules.
“My trick is to vary front tire pressure from 25 to 45 psi to adjust driver-reaction times at the starting line. The sweet spot for the rear tires is 18-22 psi,” he says.
Scott’s goal for his Bird is to run a 9-second e.t. at 130 mph in B/SA class. “It will be a real treat to see that happen,” he says. Regardless, he (and his son) continue to wave the proverbial Pontiac banner proudly in an NHRA series that’s populated by Chevys and Mopars. They truly are the last of their creed.