Interesting info on Dan Gurney:
Gurney's unusual height for a race driver caused him constant problems during his career. During the 1.5-litre era of Formula 1, Gurney's head and shoulders extended high into the windstream compared to his shorter competitors, giving him (he felt) an aerodynamic disadvantage in the tiny, underpowered cars. At nearly 6'4",[citation needed] Gurney struggled to fit into the tight Ford GT40 cockpit, so master fabricator Phil Remington installed a roof bubble over the driver's seat to allow space for Gurney's helmet—now known as a "Gurney bubble". In a fortunate error, the Italian coachbuilder that built the body for the 1964 Le Mans class-winning closed-cockpit Cobra Daytona GT coupe, driven by Gurney and Bob Bondurant, mistakenly made the cockpit "greenhouse" two inches too tall — the only thing that permitted Gurney to fit in the car comfortably.
Perhaps with his "long drink of water" physical dimensions, he was one of if not the tallest drivers back then?
Most drivers today are little guys - kind of like jockeys.