Brand: ARP – Automotive Racing Products. Head Style: Hex Head. Material: 190,000 PSI 8740 Steel. Torque To Yield: No. Finish: Black Oxide Coated. Country Of Origin: USA. This listing is for a brand new complete set of ARP high performance cylinder head studs that are made in the USA. Set includes enough studs, nuts, and washers for two heads. Application Note: Sometime in 2004 GM changed the head bolt design for the LS engines from a first design to a second design set. The first design set has bolts with three different sizes: 8mm x 45mm, 11mm x 100mm & 11mm x 155mm. The second design set has bolts with two different sizes: 8mm x 45mm & 11mm x 100mm.