FANS of YouTube's Cleetus McFarland (Garrett Mitchell to his mum) may be aware that this week his stripped-down, twin-turbo LS-powered Corvette known as Leroy became the first stickshift GM car in the world to run a seven-second quarter-mile.Leroy started life as a C5 Corvette, but when Cleetus found him he had no body panels so he became a ‘Corvette Kart’, and has undergone continual development over the past 12 months.
The first engine combo was a stock-bottom-end LS1 with an LSA blower, which went high nines at the track.
Then Texas Speed & Performance came on board with Leroy’s current motor, a 427ci LS based on a factory 5.3 alloy block and boosted by twin Precision turbos. With a factory GM computer, built T56 manual ’box and toughened rear end, it dipped into the eight-second zone. Then the factory computer was ditched in favour of a Holley, and that’s when Leroy started getting really fast.
With around 300 passes on the motor, plus burnouts, drifting, road coursing, street driving and dyno pulls, Leroy kept getting quicker at the drag strip and claimed the record for the world’s quickest stickshift Corvette multiple times.
With Leroy running consistent 8.20-second quarters, it seemed like only a matter of time until it went sevens. But a recent trip to the wind tunnel uncovered what they were really up against. Without any body panels, the Corvette has the aerodynamic properties of a brick, as the open cabin acted like a parachute. Over 600hp was required just to hold speed in the big end, let alone accelerate further.
At the next few meets they kept turning up the boost and the car got closer to the goal, but just last weekend at Bradenton Motorsports Park in Florida, Leroy lifted a head and killed a head gasket after running 8.10@178mph on full send mode. The four-bolt engine just wasn’t designed for this sort of power. So on Monday they pulled it down and had Leroy ready to race again that night.
But with the boost turned up, they ran into the same problem – lifting a head – and this time water got under one of the rear tyres and it broke traction in the top end after going 5.15@144mph in the eighth-mile.
The crew was almost ready to pack up and call it a night, but Cleetus had the idea of running the car without coolant to stop the head-lifting problem so that they could set the record that night, knowing their rivals would be racing that week. You can run a car without coolant for a short while before it gets too hot, but particularly with an alloy block and heads, too much heat can warp them out of shape.
With the Texas Speed guys approving of the idea, they sent it, and after a handful of passes without coolant, Leroy was hurt but not giving up.
Finally, he ran the number: 7.82@176mph!