Pro Series Chevy Small Block 4-Bolt Large Journal Main Bolt Kit

• Fits SBC 4-Bolt Large Journal Engines: Designed for Chevrolet Gen I Small Block 4-bolt main applications.

• 190,000 PSI Tensile Strength: Heat-treated 35 chromoly steel construction.

• Hex Head Main Bolts: Provides secure installation and straightforward serviceability.

• Ideal for Rebuilds & Performance Builds: Perfect for bottom-end service and engine assembly projects.

Strengthen the foundation of your engine with the Top Street Performance Pro Series Chevy Small Block 4-Bolt Large Journal Main Bolt Kit. Designed for Chevrolet Gen I Small Block engines equipped with 4-bolt main caps and large journal crankshafts, this SBC main bolt kit provides the strength and clamping force needed to help maintain secure main bearing cap retention in street, performance, marine, and racing applications. Whether you're rebuilding a 327, 350, or 400 Small Block Chevy, these Small Block Chevy main bolts deliver dependable bottom-end fastening performance.

Secure Main Bearing Cap Retention
Designed to securely fasten the main bearing caps to the engine block, these SBC main cap bolts help maintain consistent clamping force and reliable crankshaft support. Ideal for engine rebuilds, rotating assembly service, and performance engine projects requiring dependable main cap fasteners.

High-Strength Performance Construction
Manufactured from heat-treated 35 chromoly steel with a minimum tensile strength of 190,000 PSI, this Small Block Chevy main bolt kit is built to withstand demanding engine conditions. Threads are rolled after heat treatment, tested for tensile and yield strength, and protected with a black oxide finish and oil coating for enhanced durability and corrosion resistance.

Designed for 4-Bolt Large Journal SBC Engines
Engine-specific design provides compatibility with Chevrolet Gen I Small Block engines utilizing 4-bolt main caps and large journal crankshaft configurations. These SBC main bearing cap bolts are ideal for stock replacement, engine rebuilds, marine applications, and performance engine builds.

Ideal for Rebuilds & Performance Builds
Perfect for engine assembly, rotating assembly service, bottom-end rebuilds, and performance engine projects where fresh Small Block Chevy bottom-end hardware is recommended. An excellent choice for maintaining secure main cap retention in demanding environments.

What does this main bolt kit fit?
This kit is designed for Chevrolet Gen I Small Block engines equipped with 4-bolt main caps and large journal crankshafts, including many 327, 350, and 400 applications.

What is a main bolt kit?
A main bolt kit provides the fasteners used to secure the crankshaft main bearing caps to the engine block.

Why replace main bolts during a rebuild?
Replacing main cap hardware during an engine rebuild helps ensure proper clamping force, reliable main bearing cap retention, and long-term durability.

What does "large journal" mean?
Large journal Small Block Chevy engines use larger crankshaft main journal diameters than earlier small journal engines. Main cap hardware must match the block and crankshaft design.

Is this kit suitable for performance applications?
Yes. The bolts are manufactured from heat-treated 35 chromoly steel with a minimum tensile strength of 190,000 PSI for demanding street, marine, and racing use.

What material are the bolts made from?
The hardware is manufactured from premium 35 chromoly steel and features rolled threads, a black oxide finish, and protective oil coating for durability and corrosion resistance.

What is the difference between 2-bolt and 4-bolt main engines?
A 4-bolt main engine uses four fasteners per main bearing cap rather than two, providing additional cap retention and support in higher-performance applications.

Can these be used in racing applications?
Yes. This SBC main bolt kit is suitable for performance street, marine, drag racing, and other high-performance engine builds requiring dependable main cap fasteners.