Forged S/B Chevy Rotating Assembly, 421 Flat Top, 400 Mains, 6 Rod
421 Chevy Small Block V8, Forged Aluminum Piston Material, H-Beam Connecting Rod Type
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Speedway introduces forged rotating assemblies, with an optional balance job. Includes new 2-pc rear main seal crank, rods and pistons. Cranks are new so they use standard size bearings.
All Scat 4340 cranks are 2-piece rear main seal, internally balanced and weigh approximately 51-55 lbs. All balancing is done with our state-of-the-art Hines balancer by race mechanics with over 30 years of experience! A kit purchased with the optional balance job will ship in 24-48 hours. These rotating assembly engine rebuild kits may require additional charges for heavy metal.
If you are going to run this crank in a sprint car motor, you must have the crank flange turned down prior to balancing the crank to allow it to go through the motor plate.
NOTE: Piston rings are not included and must be purchased separately. Use Style E rings.
50 cc 14.0:1 compression ratio
- 415/421-ci SBC (3.875-inch stroke)
- Displacement: 421 ci
- Bore x Stroke: 4.155 x 3.875 inches
- Compression: 10.7:1
- Rod: 6.00-inch
- Scat 4340 Forged Steel Crankshaft
- Standard size journals
- Straight shot and chamfered oil holes
- Nitride hardened and shot peened
- Lightening holes in all rod throws
- Large radius on all journals
- KB Signature Series Forged Pistons
- 2618 aluminum alloy construction
- T-6 heat treated
- 4.000" bore pistons available in standard, .030, .040, or .060 sizes
- 4.125" bore pistons available in .030 or .040 sizes
- Speedway 4340 H-beam Connecting Rods
- Full floating pin in silicon bronze bushing
- Precision bolt bushings to positively locate cap
- 6.0" lengths
- 634 grams
- Weight matched set of 8 rods
- King HP Series Main & Rod Bearings
- 0.015" thick top layer for superior macro particle embedability and conformability
- 40 Vickers hardness to resist overlay migration and extrusion
- 450°F heat threshold for superior protection against friction and overheating
- Mains are 3/4 grooved for improved oiling to the rod journals
- Bi-metal aluminum silicon alloy featuring fine micro-bore finish
What's In The Kit
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