Chevy 350 Rod Bolt Torque and Stretch Specs
Chevy 350 connecting-rod bolt torque and stretch reference for Chevrolet Performance 3/8-inch powdered-metal rods, plus aftermarket cautions.
For the 3/8-inch powdered-metal connecting rods in the cited Chevrolet Performance 350 HO and SP350/357, Chevrolet prefers 0.006-inch bolt stretch. Its alternate method is 20 lb-ft plus 55°, or 45 lb-ft when an angle gauge is unavailable. These values do not apply to every stock or aftermarket rod bolt.
Connecting-rod bolts experience alternating tensile load every engine revolution. Correct preload keeps the cap clamped to the rod and protects the parting surfaces and bearing bore.
Torque is affected heavily by thread and under-head friction. When a manufacturer publishes a stretch range and the bolt ends are accessible to a stretch gauge, measuring elongation gives a more direct indication of preload.
Interactive rod-bolt stretch workflow
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The visual follows the measurement cycle: relaxed length, staged tightening, target stretch, and bore/rotation verification.
Chevy 350 Rod Bolt Torque Specs
| APPLICATION / ITEM | SPECIFICATION | NOTES |
|---|---|---|
| Preferred method | 0.006 in stretch | Chevrolet 3/8-in powdered-metal rod bolt |
| Torque-angle alternative | 20 lb-ft + 55° | 27 N·m + 55° |
| Without angle gauge | 45 lb-ft / 61 N·m | Chevrolet alternate for cited hardware |
| Aftermarket bolt | Use bolt maker's stretch/lube spec | Do not transfer the Chevrolet number |
Rod-bolt stretch is the more direct measure of fastener preload when the bolt maker supplies a stretch target. Bolt diameter alone is not enough to select a torque.
How to use this specification correctly
- 01
Identify the rod and bolt by manufacturer, part number, diameter, material, and whether the fastener is reusable.
- 02
Clean and inspect the rod, cap, threads, bolt spot faces, and locating features; keep each cap with its original rod and orientation.
- 03
Apply only the specified lubricant to the threads and under-head or nut surface.
- 04
Measure and record each bolt's relaxed length if using the stretch method.
- 05
Tighten both sides in controlled stages, alternating to draw the cap down evenly.
- 06
Measure final stretch or complete the specified torque-angle procedure, then verify rod side clearance, bearing clearance, and free crank rotation.
- 07
After disassembly, reject bolts that do not return within the manufacturer's allowable permanent-length limit.
Why 45 lb-ft is not universal
The Chevrolet 45 lb-ft alternate belongs to a defined powdered-metal rod and 3/8-inch fastener. Different bolt materials, thread pitch, nuts, capscrew designs, and assembly lubricants produce different stretch at the same torque.
Torque-angle versus stretch
Torque-angle reduces some friction variation by adding a controlled rotation after a seating torque. Direct stretch measurement goes further by checking the bolt's actual elongation. Use whichever validated method the rod or bolt maker specifies.
Assembly checks
- Cap and rod match marks aligned
- Bearing tangs and shells correctly seated
- Specified lubricant only
- Bolt stretch or angle recorded
- Big-end bore and bearing clearance verified
- Crank rotates freely after each rod pair
Chevrolet 350 Small-Block (5.7L V8) specifications can change by model year, engine, platform, wheel, and installed component. Confirm the VIN or engine identity, part numbers, fastener condition, and the current manufacturer instructions before service.
Chevy 350 Rod Bolt Torque and Stretch Specs FAQs
What is Chevy 350 rod bolt torque?+
For the cited Chevrolet Performance 3/8-inch powdered-metal rods, Chevrolet prefers 0.006-inch stretch and lists 20 lb-ft plus 55°, or 45 lb-ft without an angle gauge.
Can I use 45 lb-ft on ARP rod bolts?+
Not unless the exact ARP instruction says so. Use the part-specific lubricant, torque, and stretch range supplied with the bolt or rod.
Is rod-bolt stretch better than torque?+
When the manufacturer provides a stretch target and the bolt can be measured correctly, stretch is a more direct indication of preload than torque alone.
Can connecting-rod bolts be reused?+
Reuse depends on bolt design, service history, relaxed-length change, and manufacturer limits. Replace any bolt that exceeds its permanent-stretch limit or has unknown history.
Why alternate between the two rod fasteners?+
Alternating staged tightening helps seat the cap evenly and reduces the chance of distorting the big-end bore.
Technical sources
TorqueSheet favors engine- and component-specific manufacturer instructions over unsourced universal values.
1Chevrolet Performance 350 HO Base Engine guide (P/N 12366576)Primary Chevrolet Performance installation and specification manual for the 350 HO crate engine.↗2Chevrolet Performance SP350/357 Deluxe guidePrimary Chevrolet source for 0.006-inch stretch and the torque-angle alternative.↗