This brake rotor combines the strength of a 75-81 Ford-style hub (Granada) with the lighter design of the metric brake rotor for an unbeatable lightweight and durable package. AFCO engineers designed this rotor with the latest CAD software and testing methods. Manufactured to withstand rigorous racing environments, the AFCO Hybrid Rotor uses totally new castings designed and built specifically for racing. It will remove up to 12 lbs. of sprung weight on the front of your car to improve front to rear weight bias and wheel control. Uses GM metric caliper Ford 74-80 Pinto Spindle Strong and Lightweight Safely remove up to 13 lbs from the front of your car vs stock rotor 14.8# total rotor weight with 5/8" studs 10.13" diameter .813" thickness (pad spacer recommended) Stud Length:1.65 Stud Diameter:0.63 Rotor Thickness:0.81 Weight:14.80 5/8" Coarse Studs on 5" x 5" Pattern