Also I would get the RC monster heat sink, It serves 2 purposes.
1. Keeps the motor cooler
2. prevent the end cap from 'popping' off
http://www.rc-monster.com/proddetail.php?prod=RCM01
Sorry, I don't know what the run time will be on 5000Mah, but surf through this and you can get an idea of someone with a close setup:
http://www.rc-monster.com/forum/showthread.php?t=6423