Billet Specialties radiator caps are 2.5” diameter and are machined from 6061-T6 billet aluminum. Knurled sides provide a positive grip. Available in 7lb or 16 lb applications, the billet top and radiator cap come unassembled to allow for proper positioning of the logo. 7LB RADIATOR CAPS ARE INTENDED FOR USE WITH PRE 1966 RADIATORS.$19.95 EACH