This Shaft Mount Aluminum Roller Rocker Arm Kit from COMP Cams is designed for Chrysler V8 383-440 applications and has rockers with a 1.6 ratio. Mounted on an ultra-durable shaft, these rocker arms are made from a high quality aluminum alloy with a tensile strength of 80,000 psi. Needle bearing trunions allow valve spring pressures of 350 lbs. open pressure, making Shaft Aluminum Roller Rocker Arms good choice for race applications.