CP-Carrillo connecting rods are fully machined from a proprietary 4330m alloy forging for strength and durability and are available with 2 types of bolts: The standard WMC-H7 (H11) bolt with a UTS of 220ksi and our upgraded CARR-S7 (MP35N) bolt with a UTS of 285ksi. The CARR upgraded bolt is a good choice if planning on revving the engine higher than 6000rpm. All our bolts are manufactured with Asymmetrical threads, each thread has a slightly di_x001F_erent design than the previous giving the bolts an evenly distributed thread engagement. This helps to increase the clamp load and fatigue life of the fastener. Includes Mahle steel bushing for added durability and optional Cap Relief is available to aid in oil evacuation for those that run higher loads and RPM’s lockup bearings.