I'm trying to wrap my head around this short stack motor concept. From what i've read, and correct me if i'm wrong, short stack motors generally produce higher RPMs- meaning that gearing should be changed to reflect the shift in power band. Other than that, what advantages or disadvantages are there to running short stack motors. I'm thinking of trying one out in a WGT pan car. Thanks in advance.

They have less wire wound around the stator so there is less resistance. My experience says that they make just as much torque but more top end power. There really isn't more to it than that which is why all the fast motors are short stacks.