This custom valvespring kit goes far
beyond typical "performance" spring kits. Rather than double
springs or springs that are much too stiff (and add increased
resistance and wear because of it), these are an engineered
Designed for use with the Sunbelt
SportCams, this kit was designed with extensive Spintron testing.
This ensures the springs apply the correct amount of pressure to
keep the valves in contact with the cam lobes, without any
unnecessary brute force (less parasitic losses and wear/fatigue).
This kit will allow the valvetrain to rev to 9,500 only with
Sunbelt cams, but most engines will be bottom-end rev limited well
below this level - we suggest a non-sustained maximum limit of
7,400 for 3L and 7,200 for 3.2L engines.
Kit includes valvesprings and
retainers. Non-M kit includes appropriate M3 spring seats. Fits all
1992-2000 M50 engine cars, including 323, 325, 328, M3, and
is currently empty