KV rating: This figure indicates the RPM of the motor per 1volt of electricity. For example, a 2000KV motor powered at 1v can turn up to 2000rpm. When powered at 7.4v, it can turn up to 14,800rpm.
For big vehicles like monsters and 1/8 scale the KV ratings are generally lower than those used in 1/10 and smaller vehicles. E-Revo andSavage Flux come from the factory with motors in the low 2000s KV rating, I believe about 2200. With 6S power these beasts and break speeds over 60MPH! Now, keep in mind that while installed in a vehicle these motors won't hit their maximum RPM in most cases.
Here's an example of a system that you could potentially use in your rig: https://www.ssl-stormerhobbies.com/c...=ns&pn=CCM6201
I don't think you're going to find anything for much less than $200 that will still power a large vehicle without burning up. Hobbyking may have something but I haven't checked. You'll want to use 4S LiPopowerorgreater (14.8v - 22.2v) and a higher MAh ratingto maximize run time. Be sure that you have a charger that can charge fast enough, otherwise you'll have to wait a while for the batteries to recharge.