you might be able to squeeze an hour or so out of a 5k pack and a 10.5 setup on plastic tires.  novak is a not bad, and proven setup, speed passion would also be a good setup, i personally am not as much a fan of mambas but a mamba 4600 will work nicely for a drift setup.  but you probably are better off like my man said before getting two 5k packs so u can run more continuously.  if money is an issue find some nic nimh packs and run those.