JGhyperX Intake Manifold Bolt Kit 12-Piece 3/8"-16 x 1-1/8" Black Oxide — Grade 8 12‑Point

JGhyperX 38400 is a 12-piece Grade 8 intake manifold bolt kit with 12-point heads and a black oxide finish, designed as a direct replacement for common small-block V8 and 90° V6 engines.

If you're replacing or upgrading an intake manifold, the right fasteners matter. This kit supplies twelve Grade 8 carbon-steel bolts plus twelve washers that match 3/8"-16 threads at 1-1/8" length, providing stronger clamping, tighter clearance and greater durability than stock hardware. The 12-point head shape lets you access bolts in narrow engine valleys, while the black oxide finish improves heat resistance and reduces the chance of seizing over time.

What engine applications will these bolts fit?

These bolts are manufactured to fit a wide range of classic American V6 and V8 small-block engines. They are intended as direct replacements where 3/8"-16 x 1-1/8" intake manifold bolts are specified, matching original part numbers like 38400, 8504 and 134-2101.

• Compatible with Chevy Small Block 262–400 and 90° V6 engines
• Fits Mopar 273–360 applications and AMC 290–401 V8s
• Direct replacement for OE-style 38400 / 8504 / 134-2101 bolts

How do the Grade 8 and 12-point features benefit installation?

Grade 8 carbon steel delivers higher tensile strength than lower grades, giving a more secure clamp for intake manifolds—especially useful with performance gaskets and high-torque installs. The 12-point rounded head provides more engagement angles for sockets, which helps in confined engine bays and reduces rounding of the fastener head.

• Grade 8 steel for improved clamping and strength
• 12-point head allows easier socket access in tight spaces
• Rounded corners reduce tool slippage and head damage

What does the black oxide finish do for the bolts?

Black oxide is a thin chemical coating that enhances corrosion resistance and provides a smoother surface for assembly. It helps the bolts resist heat and corrosion better than bare steel, reduces galling during installation, and offers light lubricity so washers and threads move more predictably.

• Improves heat resistance around hot intake surfaces
• Reduces corrosion and thread seizing over time
• Gives a low-friction surface for easier torqueing and removal

What's included and how do I use the kit?

The kit arrives as a ready-to-fit set: twelve bolts and twelve matching washers sized for common intake manifold installations. Use standard 12-point sockets or crowfoot tools, follow torque specs for your engine, and replace bolts in sequence to ensure even clamping across the manifold.

• 12 x Grade 8 12-point bolts, 3/8"-16 thread, 1-1/8" length
• 12 x matching washers for proper load distribution
• Intended for intake manifold retrofit, replacement, or performance installs

Who is this for: Mechanics, restorers and performance hobbyists who need reliable, OE-compatible intake manifold fasteners for Chevy small-blocks, Mopar engines or AMC V8s. If you want stronger clamping, easier socket access in tight engine bays and bolts that resist heat and corrosion better than plain steel, this kit provides a straightforward upgrade or replacement solution.