Many years later Sherry recounted meeting Duntov at a Corvette show. At the time his speech was even more inscrutable, the result of a stroke he had suffered in the late '60s. The old racer-engineer told Sherry, simply, "Dave best Corvette driver."
The second powerful man watching MacDonald was Carroll Shelby. A champion racer himself, Shelby was out of the driver seat due to a heart condition. But by 1962, Shelby was up to his neck in snakes-Cobras, that is. He offered MacDonald a driver's job for the 1963 season and the erstwhile Corvette specialist scooped it up.
The 260ci Cobra roadster was a brute, but as soon as the 289 Cobra arrived, it was obvious the car would dominate its class. MacDonald took 13 checkered flags and three Second Place finishes in 23 races with Shelby's sports car. Even the arrival of the Z06 couldn't put the Corvettes ahead of the 1,000-pound-lighter Cobras. The Sting Rays would just have to wait for the big-blocks to arrive.
Of the 32 events MacDonald entered in 1963, he took First Place 15 times, including wins in the two biggest and richest sports-car races in America, the LA Times GP and the Monterey Pacific GP. He also took five Second Place finishes. In 29 of those races, he drove for Shelby in the 289 Cobra or the tube-chassis King Cobra. The other three rides were on the NASCAR circuit, where he earned two Second Places, one for Holman Moody and the other driving the famous Woods Brothers No. 21 car.
Nineteen sixty-four should have been MacDonald's breakout year. In those days, there was a common career path for racing drivers. Often they started in dirt-track and Midget cars, progressing to stock or sports cars. The Indy 500 was the obvious next step. Mickey Thompson asked MacDonald to drive his radical mid-engine, Ford-powered Sears Allstate Special. However, MacDonald was still under contract with Shelby, who had already agreed to "lend" him out Bill Stroppe for three NASCAR races. Shelby signed off on the deal, but only after Thompson agreed that MacDonald's time at the Brickyard wouldn't get in the way of his Cobra commitments.
From January to May, MacDonald racked up four wins and two Seconds, including a win at the 1964 12 Hours of Sebring with co-driver and friend Bob Holbert in the Daytona Cobra. MacDonald also had his first showing at NASCAR's Daytona 500, driving Stroppe's Mercury to 10th place. His last race before Indy was at the U.S. Road Racing Championships in Kent, where he outdueled Jim Hall and his Chevy-backed Chaparral to score his final victory.
Sherry MacDonald has said that Dave's goal was always to drive Indy, and that he accepted Thompson's 1964 offer without hesitation. "Dave never told me about the poor handling of the Thompson car, but it seems he told everyone else. Carroll Shelby said he told Dave not to drive it, and that he'd build him a better Indy car for 1965. But Dave told Carroll and other drivers that he felt obligated to Mickey, and that if he got out of the car, he'd be voted ‘candy-ass of the year.' (Several other drivers reportedly advised MacDonald not to take the ride. Jimmy Clark said, "Get out of that car mate, just walk away!")
"Maybe he thought he could handle it, I don't know. I hadn't planned to attend the race because Dave felt he wouldn't win with this car, but circumstances changed, and I did go."