Motor Suggestion for Dual Brushless Stampede

[Mephiston]

What about runtime ??

Would it be different from small motors or large ones ?

Also what kind of runtimes would i get from running 2 7 volt packs in series, if i had 3800 packs and 2 motors it would be 1900 Mah per motor ? Which would be pretty short runtimes, or does it not work that way.

I figure i might as well find out all i can about this so i don't buy something i regret.

Thanks for all the help everyone!