SKU: B627144030 | UPC: 793348041032
Eagle Pro Street Balanced Rotating Assembly – Chevrolet Small Block 408 ci (4.030″ Bore x 4.000″ Stroke)
The Eagle Pro Street balanced rotating assembly for small block Chevrolet engines delivers a complete, internally balanced 408 cubic inch kit built around a 4140 forged steel crankshaft and 4340 forged I-beam connecting rods. Designed for street performance and moderate racing applications up to 700+ hp, this kit includes forged pistons, plasma-moly file-fit rings, and high-performance bearings – providing a reliable foundation for stroker 350 builds with improved displacement and torque.
Key Features
- 4140 Forged Steel Crankshaft: 4.000″ stroke with 350 main journals (2.448″) and standard SBC rod journals (2.100″).
- 4340 Forged I-Beam Rods: 6.000″ length with 7/16″ ARP 8740 cap screws – rated for 700+ hp.
- Forged Pistons: 4.030″ bore, dish or flat top (compression ratio varies by head/chamber).
- Plasma-Moly File-Fit Rings: 1/16″ – 1/16″ – 3/16″ ring pack for low friction and excellent sealing.
- Clevite H-Series Bearings: Tri-metal rod and main bearings included.
- Internally Balanced: No heavy metal required – ready for assembly.
- RPM Capability: Safe to 6,500+ RPM with proper components.
- Made in USA: Manufactured and assembled by Eagle Specialty Products.
Product Notes
- Part number: B627144030 (408 ci Pro Street kit).
- Crankshaft: 4140 forged steel, non-twist forging, nitrided for durability.
- Rods: 4340 forged I-beam with ARP 8740 bolts – bushed for floating pins.
- Pistons: Forged 4032 or 2618 alloy (varies by batch) – typically -18cc dish for ~10:1 compression with 64cc heads.
- Balanced to ±2 grams – ready for installation.
- Total kit weight approximately 135-145 lbs.
- Requires 4.030″ bore block (350 block bored .030″ over).
Installation Notes
- Professional engine builder assembly required.
- Clearance check all components (piston-to-valve, rod-to-cam, etc.).
- Use high-zinc break-in oil and follow proper ring seating procedure.
This Part Fits
| Engine | Block | Bore | Notes |
|---|---|---|---|
| Chevrolet Small Block V8 | 350 ci (4-bolt or 2-bolt main) | 4.030″ | 1967-2002 SBC blocks |
| Stroker Builds | Dart, World, GM, etc. | 4.030″ | Requires clearancing for 4.000″ stroke |
Why Choose Eagle Pro Street?
- 30+ years of crankshaft and rotating assembly expertise.
- Pro Street series offers forged 4140 crank and 4340 rods at an affordable price point.
- Trusted by engine builders for street and strip 408 SBC builds.
Frequently Asked Questions
- Q: What compression ratio?
- A: Typically ~10:1 with 64cc heads and -18cc dish pistons – confirm with your heads.
- Q: Is it externally balanced?
- A: No – fully internally balanced for use with neutral balance flexplate/flywheel.
- Q: Does it include a balancer or flexplate?
- A: No – crankshaft only; uses neutral balance damper and flywheel.
Shipping & Handling
- Method: Freight truck (heavy crate).
- Package Weight: Approximately 160–180 lbs.
- Crate Dimensions (approx): 42″ × 24″ × 24″.
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