At the Track
Gary "Marty" Atkins
Gary arrived at our Shootout ready to see if new M/T tires and an 800-cfm Quadrajet would propel his LeMans down the quarter-mile track any quicker than the M&H Racemaster Muscle Car Drag Tires and 750-cfm, square-bore carb he ran last season to a best e.t./mph of 12.62/106.69. For his first pass, he launched at 1,800 rpm and clocked off 1,320 feet in 12.95 seconds at 103.47 mph. Since the track printer had a malfunction, he wasn't able to record his 60-foot and eighth-mile numbers.
On his second pass, he stumbled off the line, as evidenced by his 2.12-second 60-foot; 13.58 seconds later, set off the trap beams at 99.32 mph. "I think we didn't give the car enough time to cool down," says Gary's crew chief Brent Flynn.
During the pass, Brent noticed black smoke pouring from the LeMans' tailpipes. Once Gary and his Pontiac were back in the pits, Brent took corrective action to lean out the overly rich Quadrajet, changing the metering rods from 0.40 to 0.52. Regardless, the LeMans still bogged off the line on its third run and e.t. remained stagnant. It was back to the pits, where Brent tightened the Q-jet's secondary flaps, and then did some test launches at 2,000 rpm. "The bog seemed to go away," he says.
Gary reports that the next day he followed Brent's advice to raise his launch rpm, and was rewarded with back-to-back 12.95s at 103.99 and 103.51 mph, respectively. "The Quadrajet has the same potential as the square-bore, but I need to spend more time tuning it," Brent says. "We'll have to wait until next season to find out if I'm right."
Asked about the event, Gary says, "It was fun to be able to test and tune at a first-class track."
Since our Shootout enforces NHRA rules, Tom installed a cast-iron intake on his GTO so it wouldn't run quicker than the 11.50 threshhold that requires a rollbar. He came to our Shootout to dial-in his 800-cfm Quadrajet. For his first pass, he launched at 1,200 rpm, crossed the 60-foot in 1.94 seconds, and recorded a 14.31 e.t. at 91.93 mph. It was nearly 3 seconds slower than he expected.
"I was immediately concerned," he told us. "I drove the GTO from my house to the track, and I didn't notice anything wrong on the 1.5-hour trip. I thought the intake gasket might be leaking, the fuel pump was going bad, or the engine was vapor-locking." After confirming his Q-jet's secondaries were functioning fine, and the distributor and timing weren't issues, Tom took his GTO for a second and third pass. Despite how hard he put the pedal to the floor, he couldn't break out of the 14s.
At lunch, he tried to troubleshoot the problem. "I remembered that I replaced the Quadrajet's gasket the day before. I pulled off the carburetor and saw that the new gasket was severely restricting the secondaries. In the pits, I used a pocket knife to trim the restriction from the gasket, feeling confident I had fixed the problem."
For his next pass, Tom launched at 1,000 rpm, taught the 60-foot a lesson it won't forget in 1.67 seconds, and triumphantly made it through the traps in 11.63 seconds at 115.38 mph. "It was a relief to finally have my GTO back at its potential," he says. On his fifth run, he earned his best pass of the day, 11.63 seconds at 115.58 mph.
And the carb tuning he had planned for the day? "I brought three sets of metering rods for the secondaries, which I never got to use because I spent too much of the day tracking down the gremlin."
Tom adds, "The Shootout is like having a NHRA dragstrip in your backyard. I liked how all the participants rooted for each other to go faster." He liked the track conditions, too. "The starting line would suck your shoes off if they weren't tied tight."
This month's Shootout participants set their sights on improving carburetor performance, which, in turn, was expected to lower e.t.'s. Unfortunately, both spent most of the event tracking down the reason their Pontiacs were performing much slower than they expected. By the end of the day, however, each felt his car was back to a good baseline and took the obstacles in stride. Conquering the track would have to wait for another day.
We're sure the cars and combos detailed in this installment will give you plenty of ideas for your project.
HPP would like to thank the management and crew at Summit Motorsports Park for their assistance in making this Shootout possible, and John Labuda, Arnie Brewer, and Billy Farrell, who helped make the day go much more smoothly.