A/C Vacuum Pump rating question

How many microns do I need to get in a A/C vacuum pump to do the job properly on my truck and how do I measure it?

To service properly, you need to draw a deep vacuum. 500 microns is your target so, you want a vacuum pump that rated at least that good to begin with. 500 microns is the industry standard for most A/C vacuum pump manufacturers. For most people and auto repair shops, a refrigerant manifold gauge should be sufficient to measure it. However, a micron gauge will be more accurate and more expensive.