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.