No Drilling required, Stainless Steel Antenna Mounting Bracket bracket fits under front hood of these vehicles:
Chevrolet Silverado 1500: 2014 -2018
Silverado 2500, 3500: 2015 -2016 (You may need to slightly trim a rubber weather strip for access to the fender bolt and proper fitting of the bracket. Has a 3/4 inch mounting hole for optional "NMO" type mounts. Use an Optional NMO Cable and an Optional NMO to 3/8-24 adapter for regular bolt-in CB antennas.
GMC:
Sierra 1500: 2014 -2018
Sierra 2500, 3500: 2015 -2018 (You may need to trim a rubber weather strip for access to the fender bolt and proper fitting of the bracket.
Bracket Only, Required Antenna and Cable assembly not included.