It depends on the model of your vehicle. For example, the 2002 Chevy Silverado 4.8 spark plug gap is 0.060”, but you can also find a spark plug gap for Silverado 4.8 measured at 0.040”. Choose the appropriate 4.8 Vortec spark plug gap based on the manufacturer recommendations for your vehicle. If the option you choose has a different Chevy 4.8 spark plug gap, you might be able to change it with your tool.