These studs have been on a world wide backorder for several months. We are the largest ARP BP dealer with heavy allocation and even our back logs are not due to ship until November. We've since started production on our own Ultra Duty head studs for higher horsepower applications. Our Ultra Duty studs are due to start shipping within 2 weeks! Find them here: Ultra Duty 220 Head Stud System - BP Miata 1.6L/1.8L
There are many important reasons to use ARP head stud kits for your 1.6 or 1.8 Mazda Miata, including the elimination of lifting your head, as well as protecting the threads in your engine block. Every ARP head stud kit exceeds the most stringent aerospace specifications. All kits come complete with hardened parallel-ground washers and aerospace quality nuts. The studs are manufactured from 8740 chrome moly steel, heat-treated in-house to 190,000 psi tensile strength, and precision J-form threads rolled after heat-treat to create a fastener that has threads 1000% stronger than others.