I had done some quick math and for the same torque as a 5055 motor with a 14:70 gearing on 6.5" we would need roughly a 10070 motor (100mm diameter, 70mm length)
As an example, lets say that we have a 100mm wheel with a 14:40 gear ratio and a 6355 motor
to keep the torque with a similar motor geometry, just scaled up, first we restrict the motor diameter to 80mm, even that is really close to the ground
We would need a 8097 motor, ultra wide truck needed