Part details & fitment
9mm Kit includes Aasco HP109 High Performance Valve springs, HP10T9 Titanium spring retainers and HPSS Spring Seats. Our Valve Springs are designed and manufactured to specifically fit the envelope of a Porsche application not a spring from another use. It operates a higher natural frequency than the original spring for racing and at the very least minimizes damage from over rev in track day situations. 911, 914, 930, 935