24-70L vs 24-105L BEST ACTION

Hey guys. Im still getting one of these two options but i have a new condition to consider.

If i wanted to take some shots of some action like motorsport or field sports like soccer or athletics, which lense (on a 7D) would suite my need better?

I realise both probably arent built primeraly for action...but, in regards to stopping fast moving action, which would suite my needs better.

Would the better stop of f2.8 over f4 be better or would the IS be better or suite my needs for this criteria better than non-IS?

Daylight is the prefered lighting. No sunset or sunrise to consider for the action shots.

the entire 70-200 range is not considered. Try and keep the suggestions to between these two options.

Thanks guys.