Though Ultra Stage1 cams are compatible with stock OEM valve springs, we recommend the use of Skunk2 upgraded High Lift Valve Springs along with Titanium Retainers (PN: 313-14-1000) for the B58 as long term durability using stock valve springs is unknown.
All Skunk2 valve springs control are made from super-clean high tensile strength chrome-silicone wire, shot peen stress relieved, and heat treated to provide consistent and reliable long term performance. Skunk2 Valve springs allow for improved engine valve control and additional cam lift beyond what is possible with OEM valve springs, and are required when running High-Lift performance camshafts.