When we ran Nitro Funny Car back in the early 2000's we almost always had 4 short blocks ready on Sunday for eliminations. We were not a "Big Funded" team, but we did not skimp on parts. There are times it is faster to change motors than repair between rounds, depending on damage. Then after the race you could repair the others. During our years running Nitro and TA/FC we never missed a round do to time limits.