Depends on how you define high or low. The higher the number of the gear ratio the fewer revolutions are made to move the vehicle. Like a Chevy with 3:42 will give you better fuel economy than the 3:77 or 4:11. The choice depends on how the vehicle will be utilized. Will you be towing a heavy trailer, will it be on flat or small hilly roads or up and down substantially, mountainous roads. If you are going to tow a medium weight trailer with a medium sized V-8 the 3:77's would be my choice. If you plan on towing a heavy trailer, the 4:11 would make the grade. If you are like me and drive a 4X4 with light towing, I chose the 3:42's. Substantial pulling power with good fuel economy. If you plan on a diesel engine the torque will make up for most of the difference. I would stay with the highest number availalbe.