jags don't really like 24v and high amperage...
since this isn't for first i can recommend these.
http://holmeshobbies.com/product.php...4&cat=2&page=1
they are a little more expensive ($100) but will take the amps/voltage. 24v, 80a and have a bec.
also
http://killerbotics.com/kbtools/TentacleTools/ has a pretty cool drivetrain calculator that has those motors on it.