Ferrea GTR Valvetrain Kit Dual Spring – no valves

Yes. This specific kit is engineered to be a direct drop-in upgrade for the R35 GT-R cylinder heads using standard size, stock OEM intake and exhaust valves.

Factory springs are weak and can allow 'valve float' at high boost or RPM. Dual springs provide the necessary seat pressure to keep the valves controlled under increased load, even without changing the valves themselves.

Titanium retainers are approximately 40% lighter than factory steel units. This reduction in valvetrain mass improves engine response and allows the engine to rev higher safely without valve float.

Generally, no. Since this kit utilizes stock valves and fits the factory spring pockets, it does not typically require the seat cutting or machining associated with oversized valve upgrades.

No, this is a complete solution. It includes the high-pressure dual springs, titanium retainers, spring locators, keepers (locks), and fresh valve stem seals for a full refresh.