To make these even faster, the cars could roll through the box without stopping. Eliminate the fore & aft jackmen. Install riseable rollers or a conveyor belt in the center of the pit box, to catch the skid plank. The step planes on the floor of the car could provide lateral alignment to prevent the car sliding off the roller/belt. Line the tire removers and tire mounters sequentially. Car enters the box, rolls on the riser, 4 wheelnuts off, 4 tires off, 4 tires on, 4 wheelnuts on, car drops off riser, done. Return to racing.