Carefully specified for the Miata, these springs are part of the ideal NA/NB Miata head. The titanium retainer's light weight means there's less reciprocating mass. The well-matched spring rate means your valves are better controlled at high engine speed but without the drag and extra stress of a too-stiff spring. In turbo cars, the exhaust valves will seat better even under high backpressure. As an added bonus, they also allow for greater lift (12mm or 0.472") if you're running different cams. They are designed to allow engine speeds of up to 9000 rpm before valve float - but if you're planning on doing that repeatedly, we do recommend using our dual springs instead.
Aluminum spring seat, chrome silicon steel spring and titanium retainer. Sold in sets of 16 for a complete head. Fits all NA and NB Miatas. NA valves will require the use of valve keepers from a NB engine (not included).
||58 @ 34.10
||157 @ 10.5
||56 @ 34.2
||154 @ 10.5