Brand: ARP Manufacturer's Part Number: 300-8249 Part Type: Rocker Arm Nuts Product Line: ARP Perma-Loc Rocker Arm Adjusters Automotive Fittings Part Number: ARP-300-8249 UPC: 672036012137 Rocker Arm Style: Full roller Rocker Arm Nut Style: Polylock Rocker Stud Thread Diameter: 7/16-20 in. Minimum Rocker Slot Width: 0.560 in. Overall Height (in.): 2.05/2.62 in. Shank Diameter (in.): 0.56 For Use with Stud Girdle: Yes Quantity: Sold as a set of 16. Notes: This set contains both 2.050 in. and 2.615 in. length rocker arm nuts. Description: Stop your rocker arms from loosening forever with these ARP Perma-Loc rocker arm adjusters. Made from heat-treated, premium-grade 8740 chromoly steel, these adjusters provide 190,000 psi tensile strength for the utmost in reliability. Other features include exclusive heads with special shouldered stops to hold the adjusting wrench, precision CNC-machined threads to ensure optimum seat pressure, flush-machined set screws for proper contact on the studs, and, best of all, they don't require any special tools for installation.