ARP 134-5202 Chromoly Main Bolt Kit 4-Bolt Large Journal for 67-Up SBC Gen I

Vehicle Fitment

• Universal fit for 1967-and-up Gen I Small Block Chevy (SBC) engines with a standard (non-splayed) 4-bolt main cap configuration and large journal crankshaft

Fitment Notes

• Fitment is determined by block architecture (main cap style and journal diameter), not vehicle make/model/year - confirm your specific block's main cap configuration and journal size before ordering
• Designed for standard 4-bolt main caps - not compatible with splayed-cap blocks, which require ARP's splayed-specific stud kit (e.g., 234-5602) instead
• Not compatible with windage tray mounting; a separate stud kit with standoff studs is required for that application
• This part is legal for sale or use on emissions-controlled, non-emissions-controlled, and racing-use-only vehicles, as it does not affect vehicle emissions

Features

• Popular premium upgrade over factory main fasteners for daily street builds through moderate performance applications
• Rated at 180,000 psi tensile strength
• Forged from 8740 chromoly steel for superior strength and reliability
• Reduced wrenching head and large underhead radius for a clean, low-profile fit
• Threads rolled after heat-treating, giving roughly 2000% better fatigue strength than bolts threaded before heat-treatment
• Wide-area flange design promotes even load distribution during torquing
• Black oxide finish for corrosion resistance

Specifications

• Part Number: 134-5202
• UPC: 672036001865
• Application: Small Block Chevy (Gen I), 4-Bolt Main, Large Journal
• Main Cap Style: Standard (Non-Splayed)
• Fastener Style: Bolt (Hex Head)
• Tensile Strength: 180,000 psi
• Material: 8740 Chromoly Steel
• Finish: Black Oxide
• Category: Main Bolt Kits

Included Components

• 8x Chromoly Main Bolts (Hex Head)
• Hardened Parallel-Ground Washers

Product Description

The ARP 134-5202 is a high performance main bolt kit built for Gen I small block Chevy engines running the standard 4-bolt main cap configuration with a large journal crankshaft - the most common bottom-end architecture across decades of SBC-based builds since 1967. It's a direct, premium upgrade over factory main fasteners, addressing the fastener failures that first led ARP's founder to start the company back in the early 1970s.

Each bolt is forged from 8740 chromoly steel and rated to 180,000 psi tensile strength, with threads rolled after heat-treating rather than before - a process that gives roughly 2000% better fatigue strength than bolts machined the conventional way. A reduced wrenching head and large underhead radius keep the fit clean, while the wide-area flange spreads clamping load evenly across the cap during torquing, and hardened parallel-ground washers are included for consistent, accurate torque readings.

This kit is a common choice for street/strip builds and daily-driven performance engines that don't need the added precision of a full stud kit but still benefit meaningfully from moving past factory-grade main bolts. For splayed-cap blocks or engines running toward the top of the RPM range, ARP's stud kit line (e.g., part 234-5602) is the better-suited upgrade.