How to identify a 400 SBC crankshaft?
Identifying a 400 Small Block Chevy (SBC) crankshaft can be crucial for enthusiasts and mechanics alike, especially when it comes to performance upgrades or engine rebuilds. The 400 SBC, produced from 1970 to 1980, has unique characteristics that set it apart from other small block engines. In this article, we will explore the key features and methods to accurately identify a 400 SBC crankshaft.
Key Features of a 400 SBC Crankshaft
The 400 SBC crankshaft has several distinctive features that can help you identify it:
- Stroke Length: The 400 SBC crankshaft has a stroke of 3.75 inches, which is longer than the 3.48 inches found in the 350 SBC crankshaft.
- Counterweights: The 400 crankshaft features larger counterweights to balance the longer stroke, which can be visually identified as they are more pronounced compared to those on a 350 crankshaft.
- Part Number: Look for the part number stamped on the crankshaft. The 400 SBC crankshaft typically has a part number starting with "3932442" or "3932441" for the earlier models.
- Journal Size: The main journal size for the 400 SBC is 2.65 inches, while the rod journal size is 2.10 inches, which is consistent across all small block engines.
Steps to Identify a 400 SBC Crankshaft
To accurately identify a 400 SBC crankshaft, follow these steps:
- Remove the Crankshaft: If the crankshaft is still in the engine, you will need to remove it for proper inspection.
- Clean the Crankshaft: Thoroughly clean the crankshaft to remove any oil or debris that may obscure the markings.
- Inspect for Part Numbers: Look for the stamped part numbers on the crankshaft. Use a flashlight if necessary to see them clearly.
- Measure the Stroke: Use a caliper to measure the stroke length. If it measures 3.75 inches, it is likely a 400 SBC crankshaft.
- Check Counterweights: Compare the size and shape of the counterweights with those of a known 350 SBC crankshaft to confirm the identification.
Conclusion
Identifying a 400 SBC crankshaft is essential for anyone involved in engine performance or restoration. By understanding its unique features and following the outlined steps, you can confidently determine whether you have a 400 SBC crankshaft in your possession. Whether you're a seasoned mechanic or a car enthusiast, this knowledge will help you make informed decisions about your engine projects.
Frequently Asked Questions
What is the specs of the 400 crank?
Additional information
| Weight | 54 lbs |
|---|---|
| Snout | Standard |
| Stroke | 3.480, 3.750 |
| Rod Length | 5.7 |
| Rod Journal | 2.1 |
What is a 350 bored 60 over with a 400 crank?
With a 400 crank in a . 060 over 350 it would be a 388.
What was the last year of the 400 SBC?
The Chevrolet 400 was introduced in 1970, and used in full size (Impala, Caprice, etc. and midsize (Chevelle) through the 1976 model year. It was utilized in light duty trucks through the 1980 model year. They were quite common in early to mid 70's full size wagons.
What years did Chevy make the 400?
| Chevrolet 400 | |
|---|---|
| Production | 1962–1974 |
| Assembly | San Martín, Buenos Aires, Argentina |
| Body and chassis | |
| Class | Executive car |
How do you identify a 400 SBC block?
Look at the sides of the block - if they're perfectly flat, it's a 305 or 350. If it's a 400, there will be small bulges around each cylinder, between 1/8" and 1/4" tall. Chevy only made 3 different casting numbers of 400 blocks - it'll have to end in 817, 509 or 511.
What's the difference between a 350 crank and a 400 crank?
The 350 has just under three and a half inch stroke. The 400 has a three and three quarter inch stroke. And it also has a larger bore. The the bore size on a 350. Standard is four inches.
How much HP can 400 SBC handle?
With our low-compression, power-adder friendly 400-inch small-block easily exceeding 525 hp, it was time for some boost. And that's where things start to get very interesting.
How to tell the difference between a 350 and 400 SBC?
The 350 has just under three and a half inch stroke. The 400 has a three and three quarter inch stroke. And it also has a larger bore. The the bore size on a 350. Standard is four inches.
How to tell if you have a 400 crank Chevy?
Re: How can I tell a 350 crank from a 400 crank? 3951529 casting # of a 400 crank is a good definitive way unless you have a way to measure accurately..... The 2.65" main journals of a 400 crank can be turned to the 2.45" diameter of a 350, or even to the 2.30" diameter of the early small journal cranks.
How do I identify my Chevy crankshaft?
Chevrolet crankshafts have a casting number located on the rough surface of one of the counterweights or between the bearing journals.
