To many variables at a dirt track, it would almost be impossible to say that changing the timing a few degrees and or a slight gear change would make a difference, it could be a mulitude of things that can and will make the car faster or slower, just think about it.
But if it makes you more confident in your combo, you'll drive it harder, so it can make a mental difference which can be the most important change.
I'm with that other guy though dyno's dont lie, but then again nobody races dynos either.
JMO>Cp