What does the STDX sizing mean for these bearings?

The STDX designation indicates that these are undersize bearings. They are designed to be used when the crankshaft main journals have been machined down (ground) to a smaller diameter, typically during an engine rebuild. It's important to measure your crankshaft journals to confirm they match the undersize specification for these bearings.

What is the PMaxBlack overlay and Radialock technology?

PMaxBlack is a specialized overlay applied to the bearing surface that enhances its ability to handle higher loads without damage. Radialock is a feature designed to help the bearing achieve the correct 'crush height' when installed, ensuring it seats properly and maintains consistent contact within the engine block.

Are these bearings suitable for a high-performance engine build?

Yes, the PMaxBlack overlay and tri-metal construction are designed for superior load capacity, making them a strong choice for performance applications. However, always ensure your engine's specific requirements and tolerances are met for any build.

King Engine Bearings General Motors 326/350/389/400 (Size STDX) Main Bearing Set

Specifications

Brand: King Engine Bearings
Part #: MB5511XPSTDX
UPC: 611500598678

King Engine Bearings General Motors 326/350/389/400 (Size STDX) Main Bearing Set

Name: King Engine Bearings General Motors 326/350/389/400 (Size STDX) Main Bearing Set
Brand: King Engine Bearings
Price: 186.43 USD
Availability: InStock

$186.43

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King Engine Bearings main bearing set for GM 326, 350, 389, 400 engines. Size STDX. Features PMaxBlack for superior load capacity.

Key Features

Fits a wide range of General Motors engines including 326, 350, 389, and 400 cubic inch V8s.
Features PMaxBlack overlay for superior load capacity.
Includes Radialock technology for optimal crush height.
Constructed with a tri-metal copper-based material for durability.
This is an STDX size bearing, which is an undersize bearing for crankshaft journals.

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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Product Details

King Engine Bearings specializes in making top-notch engine bearings, and this main bearing set is built for a range of General Motors engines, including popular applications like the 326, 350, 389, and 400 cubic inch V8s. If you're rebuilding the bottom end of your engine, these bearings are a solid option to ensure smooth operation and longevity. They are designed to handle the demands of these classic GM powerplants.

What sets these bearings apart is their PMaxBlack overlay, which offers superior load capacity, meaning they can withstand higher pressures without failing. They also feature Radialock technology for optimal crush height, which helps ensure the bearing stays securely in place within the engine block. The tri-metal copper-based material provides a good balance of strength and wear resistance, crucial for main bearings that support the crankshaft.

This set is specifically sized STDX, which is an undersize bearing. Always ensure you've checked your crankshaft journals for the correct size before ordering. King has been focused on bearing technology since 1960, aiming to provide the highest quality bearings available.