What is the racing format where drivers predict their elapsed time?

The racing format where drivers predict their elapsed time is bracket racing.

Before a run, each driver selects a “dial-in” time—the elapsed time they expect their car to need to reach the finish line. The starting system then gives the slower-dialed car a head start equal to the difference between the two predictions. A car that runs quicker than its dial-in “breaks out” and can lose, making consistency more important than outright speed.

Bracket racing grew as a way to let cars with very different performance levels compete fairly. It rewards accurate prediction, repeatable driving, reaction time, and mechanical consistency rather than simply having the quickest machine. Some bracket events are also informally described as “run-what-ya-brung” racing.

Index racing is related but different: competitors generally aim to run a specified performance index, while heads-up racing starts opponents together without a handicap. Pro Stock is a professional vehicle class, not the name of this timing format.