For the most extreme Miata engine. If you're building a track car, are planning on extended run time above 7500 rpm or boost 18 psi or more - they're what you need.
Aluminum spring seat, chrome silicon steel springs 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).
||74 @ 34.2
||177 @ 10.5