Hi all,
I have been practicing lots of day photos and getting used to all my settings. Although i am attending some drag racing on the weekend and im not too familiar with shooting in low light, especially fast moving objects.
I have a Canon 7D with the following lenses:
-50mm 1.8 II
-18-35mm 3.5-5.6
- 70-300mm 4-5.6

What would be the best setting (TV, AV, M) and lens for these shots and what techniques can i use to get sharp well exposed photos? My understanding is that i will need a high ISO, a small f/stop and a fast shutter speed. But judging the light at the time and choosing the right numbers is my major issue.

Any help will be appreciated.