If it’s one thing that the year 2020 has neglected us of, it’s spending time at the dragstrip. With the absence of racing and car shows in some states, we’ve had to scramble to find feature cars and racing records.
Photo: Sebastien Imbeault
In a previous article, we feature Sebastien Imbeault’s 9-second naturally aspirated C6 Z06. The French Canadian from Baie-Comeau purchased the C6 in 2008 and has been chopping at the records ever since. At the time of the previous article, Imbeault was the first to get a stock LS7 rotating assembly and pistons in the 9.20s. AR Fabrication built the powerplant after the engine needed to be freshened up.
At the time of the first article, Imbeault said that he thought that the Z06 could go low 9s with the right conditions. However, we thought it might be able to go faster and crack the 8s. Even though it has taken some time, Imbeault did break his record and smashed into the 8-second range with his manually shifted 427-cubic inch engine. His new record was established at Napierville Dragway in Quebec, where he managed an 8.993-second 1/4-mile pass. Imbeault said, ” It was a tough run in less than ideal conditions. We were fighting a nine mph headwind and running into all sorts of gremlins.”
For the new record run, Imbeault made a few changes on the Corvette since our previous article, which ultimately helped him dial back his 60-foot times. Imbeault custom-built a TR6060 transmission with carbon blocker rings and hand fit synchros. He also adjusted the gear ratio in the transmission by using parts from GM, Ford, and Dodge. Finally, he changed as well as the rear gear in the C6. The 3.42s were ditched and replaced with a 3.90 ring and pinion. The Weld RT-S wheels and 335-35-17 Hoosier drag radials were also removed for a set of Bogart lightweight 15-inch wheels wrapped with Hoosier Dr2 295/55/15-inch drag radials. Imbeault said, ” The Hoosier tires measure out at 27.6-inches, which was not my preferred choice, but apparently they worked.”
The most significant change was in the clutch setup. Imbeault said, ” I worked with Rob Smith, Owner of RPS Clutch, extensively on the BC2 clutch. Without the modifications he made, I couldn’t leave as hard out of the hole, nor would I be able to shift as fast as I can now.” Imbeault’s shift point time was between 180-200-milliseconds between shifts. This is an impressive number considering the H-pattern TR6060 is not faceplated.
Imbeault is planning to go faster in the future with a couple of more changes. “I’m working with Kohle at AHP on a set of CNC ported Brodix heads called Archangel. These heads will flow much better than stock castings using larger titanium valves. With a bit of luck, I think I can run 8.8s or maybe even an 8.79.” Time will tell if Imbeault can pull it off, but we’re certainly not counting him out.