Head bolt kits made tough in the USA.
ARP High Performance series head bolt kits are tough! They are rated at 170,000 psi--15 percent stronger than Grade 8 fasteners. They come available with hex heads or reduced wrenching 12-point heads that eliminate the need for valvetrain removal when re-torquing cylinder heads.

Leading engine builders rely on these main studs.
ARP main studs are made from 8740 chromemoly steel and have a 190,000 psi tensile-strength rating. They are precision centerless-ground and thread-rolled to Mil-S-8879 specs, with a black oxide finish for corrosion resistance. The kits come complete with hardened washers and high-strength hex nuts