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Complete HD 12v Valve Spring Kit – Springs, Retainers & Locks

Heavy Duty 12v Conical Springs, Billet Retainers & Lock Kit 
For the 1989-98 12v 5.9L engines. 

Spring Specs:

  • 170lb seat pressure at 1.940 installed height / 375lbs. at 1.275 open height
  • Coil binds 1.225
  • Designed for up-to 6,500rpm
  • safe for daily driving & race capable If your running over 40psi & 3700rpm, this is one of the kits for you. Other options available too. HD Pushrods are required to run this kit
    If you are running higher boost then stock, these springs will help the valves from being pushed open which can cause damage &/or cost you 10-12hp and some efficiency.
    High Boost capability 

This valve spring system has been engineered to work in unison with all of its included components to provide the best overall valvetrain stability. Our kit will include 12 valve springs, 12 billet steel retainers and 24 valve locks to give you everything you need to upgrade the cylinder heads valve spring assembly.

Designed with the capability to be used in applications from stock rebuilds, to all out purpose built race trucks.

With higher boost capability, improved spring shape and increased rpm capability which allows for maximum spring stability at high rpm, while also having a much lower amount of stress that the spring wire will have to live with. This in turn increases service life even in low rpm applications, while having a 6,500 rpm capability.

Increased the valve spring seat pressure to 170lbs to retain control of the valves to a higher PSI of boost, but will remain safe to run with the factory flat tappets.

Lightweight 7 deg Billet steel retainers that have been designed to mate perfectly with the conical spring shape. This retainer is much lighter in weight and stronger than OEM and other aftermarket retainers because of its reduction in size.

Also included are 7 deg valve locks to pair with these new retainers.

Every valve spring is tested in a computerized spring load cell. Each set of springs is matched within 1% of seat pressures to provide just that much more added quality.

 Don’t be fooled by people selling cheap springs out there. A broken spring can take out an engine.


Part number: D-105-Kit-12V

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