JGhyperX Intake Manifold Bolt Kit — 12-Point Grade 8, Black Oxide (12pc, 3/8"-16 1-1/8")

High-strength Grade 8 12-point intake manifold bolt kit finished in black oxide for reliable clamping and easier access in tight engine bays.

Upgrade or replace worn intake manifold fasteners with this complete JGhyperX bolt kit designed for common small block Chevy, Mopar and AMC V8 engines. Each set includes 12 bolts and matching washers made from Grade 8 carbon steel and treated with a black oxide finish to resist corrosion and reduce galling. The rounded 12-point heads are intended to give mechanics better socket access in confined engine valleys—especially useful when swapping aftermarket manifolds or working on performance builds.

Will these bolts fit my engine and intake manifold?

These bolts are manufactured to match the common OEM thread and length used on many small block V8 intake applications. They are direct replacements for part numbers like 38400, 8504 and 134-2101 and fit engines including Chevy 262–400, 90° V6, Mopar 273–360 and AMC 290–401.

• Thread size: 3/8"-16, length: 1-1/8"—designed for standard intake manifold stack-up.
• Compatible models: Chevy small block, select Mopar V8s, select AMC V8s and some 90° V6s.
• Direct replacement for common OEM numbers for straightforward swap.

How does the 12-point head help during installation?

The 12-point head offers more engagement points for a socket versus a standard hex, allowing easier alignment and access in cramped engine compartments. That rounded multi-angle design reduces the need for perfect socket positioning and helps when working around valve covers, vacuum lines and aftermarket components.

• Multiple socket entry angles for confined valley access.
• Rounded profile minimizes interference with adjacent hardware.
• Better torque transmission when using appropriate sockets for a secure fit.

What are the benefits of Grade 8 steel and the black oxide finish?

Grade 8 carbon steel provides higher tensile strength and improved clamp load compared with lower-grade fasteners, helping keep the manifold sealed under thermal cycling and vibration. The black oxide surface treatment adds mild corrosion resistance, reduces friction for smoother installation, and helps prevent seizing—important for bolts exposed to heat and oil.

• Grade 8: increased strength and durability for performance and longevity.
• Black oxide: improved lubricity for easier torqueing and removal later.
• Washers included to distribute load and protect gasket surfaces during tightening.

What’s included in the kit and how should I use these bolts?

The package ships with 12 bolts and 12 matching washers, ready for a full intake manifold retrofit or replacement. Use a calibrated torque wrench and follow your engine manufacturer’s torque sequence and specifications; consider anti-seize on threads if repeatedly servicing or if in corrosive environments.

• Contents: 12 Grade 8 12-point bolts and 12 washers—complete set for one manifold.
• Recommended practice: clean mating surfaces, replace gaskets, torque in the correct sequence.
• Optional: light anti-seize on threads for applications prone to corrosion.

Who this is for: This JGhyperX bolt kit suits DIY mechanics, professional shops and performance enthusiasts replacing worn fasteners or installing aftermarket intake manifolds on compatible Chevy, Mopar and AMC engines. It’s intended for users who need stronger, easier-to-access bolts with a protective finish for long-term reliability during high-heat and high-vibration use.