M8x40 with 1.25 pitch with 10mm head. Specbolt's "Wurks" series bolts only look expensive. Forged from High Carbon steel, these class 10.9 Hardened Nickel Plated bolts rival titanium's good looks but at a much lower price. These bolts were engineered by Specbolt in conjunction with top engine builder Rob Selvy. He is so stoked about these new bolts he even loaned us the Selvy trademarked "Wurks" name for them.