General Motors 2.2L Ecotec, 12-point nuts and under cut studs, ARP Head Studs 231-4701ARP Head Stud Kits with 12-point Nuts and Under Cut Studs .
Cylinder Head Studs, Hex Nuts, Chevy, 153, 4 Cylinder, Kit
ARP Studs are thread rolled after heat-treat, which gives them about 2000% (that's twenty times) better fatigue strength than those studs that are threaded prior to heat-treat (a very common industry practice). It costs a lot more to do it this way, because it's tough on tooling.
Cylinder Head Studs, Hex Nuts, Chevy, 2.3L, Kit