Valve spring used on 2012 Mustang Boss 302 engine Higher seat pressure than base valve spring 300 N closed 700 N open Boss 302 265 N closed 650 N open Mustang GT Installed height 40mm, same as Mustang GT 8000 rpm compatible Use with cams up to 13mm lift Can be used on base 5.0L Ti-VCT head Sold in sets of 16