The ornamental design for a clock in the shape of a racecar, as shown and described.
FIG. 1 provides a perspective view of the clock in the shape of a racecar.
FIG. 2 provides a front view of the clock in the shape of a racecar.
FIG. 3 provides a rear view of the clock in the shape of a racecar.
FIG. 4 provides a right side view of the clock in the shape of a racecar.
FIG. 5 provides a left side view of the clock in the shape of a racecar.
FIG. 6 provides a top view of the clock in the shape of a racecar; and,
FIG. 7 provides a bottom view of the clock in the shape of a racecar.
The broken lines showing a car number used in conjunction with the clock in the shape of a racecar are for illustrative purposes only and form no part of the invention.