I would like to the effect of the wind to the performance of a horserace.

1. 6f race.
  a. headwind at the backstretch 7 knot
  b. tailwind at the backstretch 7 knot
2. 7f race.
  a. headwind at the backstretch 7 knot
  b. tailwind at the backstretch 7 knot

I suppose the headwind will delay the race by 0.3 second, and the tailwind will fasten the race by 0.2 second. How much am I wrong ?

Thanks in advance.