RK Mclaren Main and Head studs



For Both M838TE and M840TE Applications

In stock (can be backordered)

SKU: MCL.ARP.RK Categories: , ,


The RK Autowerks L19 upgrade is available in either a set of main and head studs, serving as direct OEM replacements.

Main Bolt Kit: Includes 10 Large Main Bolts with sealing washers and 10 Small Main Bolts with sealing washers.

M12 Studs: Comprises 20 L19 Studs with nuts and washers.

We opted for bolts on the mains, similar to the original, to prevent any potential oil leakage, and we also provide new sealing washers.

These components are manufactured precisely to OEM specifications, requiring no adjustments to the block. In line with our commitment to high-performance track applications, we collaborated with ARP to produce these bolts using L19 alloy, ensuring a clamping force exceeding 1000psi.

These bolts are exclusively utilized in our 1300hp+ crate engines, and they are compatible with McLaren M838T and M840T engines.

Why choose L19 over 625 Custom Age? L19 and 625 Custom Age are both brand names of ARP INC. They represent alloys rather than the actual material names. L19 is akin to H11 tool steel and offers optimal stretch and torque holding capacity. Over-torqueing or reaching the yield point with a 625 Custom Age bolt can impose excessive stress on engine block castings, potentially leading to warping or cracking. It’s crucial to adhere strictly to recommended torque specifications.

L19: This premium steel boasts superior strength and fatigue properties, capable of delivering a clamp load at 260,000 psi. It finds extensive use in short track and drag racing applications where inertia loads surpass the clamping capability of ARP2000.

Additional information

Weight 15 lbs
Dimensions 12 × 8 × 5 in


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