3951509 GM Engine Block Std 400 Chevy

Review GM Chevy Bare Engine Block Bore for CHEVY STD 400 1974

The GM 3951509 is a 1974 Chevy 400 cubic inch (6.6 liters) bare engine block in standard configuration. This engine block is a cast iron monobloc design, which provides excellent durability and heat dissipation. It was originally manufactured by General Motors for use in full-size Chevrolet and GMC vehicles of the time.

The 400 cubic inch engine block features a bore size of 4.00 inches (101.6mm) and a stroke length of 3.48 inches (88.4mm). This results in a total displacement of 400 cubic inches or 6.6 liters. The block is designed to accept a forged crankshaft, forged pistons, and other performance-oriented components.

The block is equipped with a standard wet sump oiling system, which utilizes an oil pan and an oil pump to circulate oil throughout the engine. The block also features a factory-installed front oil pump drive, making it easier to install an aftermarket oil pump if desired.

The cylinder bores are honed to ensure a precise fit for the piston rings and cylinder liners. The block also features a raised oil pan rail, which helps to prevent oil from leaking out during high-performance applications.

The block is designed to accept a variety of engine accessories, including a water pump, alternator, power steering pump, and air conditioning compressor. The block also features a factory-installed front engine accessory drive, which simplifies the installation of these accessories.

The 1974 Chevy 400 engine block in standard configuration is a versatile and powerful foundation for custom engine builds. It can be used for street applications, race applications, or even marine applications with the right modifications and components. Whether you're building a high-performance hot rod or restoring a classic Chevy, this engine block is an excellent choice for your project.

Buying a GM 3951509 1974 Chevy 400 bare engine block standard (STD) has its own set of advantages and disadvantages. Here's a detailed analysis to help you make an informed decision:

1. Affordability: Buying a bare engine block is generally less expensive than purchasing a complete engine or a rebuilt one. This makes it an ideal choice for those on a budget.

2. Customizability: Since it is a bare engine block, you have the freedom to customize it according to your specific requirements. You can choose the components, such as pistons, crankshaft, and connecting rods, based on your performance goals.

3. Replacement: If your existing engine is damaged or beyond repair, a new engine block can serve as a cost-effective replacement.

1. Assembly required: A bare engine block does not come with any internal components, meaning you will need to assemble it yourself or hire a professional mechanic to do it for you.

2. Time-consuming: The assembly process can be time-consuming and may require a significant investment of time and resources.

3. Risk of error: Assembling an engine involves a high degree of precision and skill. If not done correctly, it could lead to poor performance, damage to the engine, or even safety issues.

The decision to buy a GM 3951509 1974 Chevy 400 bare engine block standard depends on your specific requirements, budget, and technical expertise. If you are on a tight budget and are comfortable with the assembly process, this could be an excellent choice. However, if you lack the time or skills to assemble the engine, or if you prefer a more turnkey solution, you may want to consider purchasing a complete or rebuilt engine instead.

If you are confident in your ability to assemble the engine and have the necessary resources and time, a bare engine block can be a cost-effective and customizable option. Otherwise, it may be wiser to invest in a complete or rebuilt engine to avoid potential complications and save yourself the hassle.

Details:

Good used standard bore block. All bolt hole threads are good, will need machine work before building it. No spun mains. I encourage this.4. Read the completely before buying.

I'm not a business or company.

specifications engineblocksam:

• for models: Std, 400
• for makes: Chevy
• for years: 1974
• brand: Gm
• mpn: 3951509
• type: Engine Block
• material: Cast Iron
• country/region of manufacture: United States
• vintage part: Yes
• finish: Unfinished

seller engineblocksam:

• city: wichita, kansas
• rating: 100.0%
• # reviews: 1420

payments engineblocksam:

• other
• wallet: google-pay
• credit card: discover

general engineblocksam:

• category: Auto Parts > Car Truck Accessories > Engines > Blocks

returns engineblocksam:

• policy: no returns

shipping engineblocksam:

offer engineblocksam:

• availability: in stock
• sold #: 14
• prices: $299.99–$999.99
• item condition: Used
• options: seller-arranged-local-pickup
• in stock #: 3
• started: october 2, 2025