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Engines and Components› Engines, Blocks and Components

Smeding Performance

383" Long Block Engine Assembly

Name: 383" Long Block Engine Assembly
Brand: Smeding Performance
SKU: 039-383LB231236
Price: 7450.00 USD
Availability: InStock

$7,450.00

SKU: 039-383LB231236

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Overview

The Smeding Performance 383" Long Block is a completely new engine built with quality parts. It features a new 4-bolt main block, forged crankshaft and rods, and roller cams with a roller valvetrain.

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This new 383" engine is constructed using 100% brand-new parts, including the block, and is engineered with performance and hot-rodding in mind. Key components include a Smeding Heavy Duty 4-Bolt Mains block with a 9.025" deck height and 4.000" bore, a Smeding 4340 Forged Steel crankshaft with a 3.800" stroke, and Smeding 5140 Forged Steel I-Beam connecting rods. It is fitted with UEM Custom Hypereutectic Aluminum pistons providing a 9.8:1 compression ratio and Smeding 1.5 ratio full-roller rocker arms. The cylinder heads are Smeding Aluminum with 180cc intake ports, 2.02"/1.60" valves, and 65cc chambers. Available in multiple configurations, including 380hp, 420hp, 450hp, and 480hp options, each with specific cam specs, lift, duration, and LSA. The recommended torque converter stall speed varies depending on the chosen horsepower rating. A 3-year, unlimited-mile warranty is included. It is important to note that the final assembly and tuning of this partial engine must be completed by an experienced engine assembler/builder. Smeding Performance is not responsible for damage caused by user-installed parts.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

Brand	Smeding Performance
Part Number	039-383LB231236
Category	Engines and Components

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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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