well for dirt oval, you may want more rpm over torque, as typically corner speeds are still really good if you can hang the ass out and hold it.
i would maybe look into a Jammin/Picco, or the OS Vspecs or VBs, they are all over 200.00 motors, but turn some very impressive Rs while still retaining relatively good torque, and strong running/lasting motors, that are easy to tune, and will hold it well.