862 Heads – Everything you Should Know

862 Heads are the best when it comes to compression due to their ability to control the flow of air and fuel into and outside the cylinder.

If you need a complex cylinder head with enough power level to aid your vehicle performance and efficiency then go for the 862 cylinder heads.

GM produced the gen III cylinder heads used in the 862 engines. Aluminum is used in the manufacturing of 862 cylinder heads. They are sand-cast and may provide greater compression than their competitors. This is helpful when examining 799 Vs. 862 head combinations.

Higher in-cylinder compression, a greater rate of heat release, and quicker ignition are all results of the cylinder head’s compression ratio.

For the internal combustion process of a car, an extremely high compression ratio is essential. In addition to the compression ratio, the 862 cylinder heads have more advanced characteristics.

Continue reading as we show you all you need to know about 862 heads before porting to them.

862 Heads Specifications

Here are some common of the 862 cylinder heads:

🚘 Intake Port Valve: Cathedral

🚘  Exhaust Port Design: D-shaped

🚘  Material: Aluminum

🚘  Manufacturer Part ID: 12559863

🚘 Intake Port Volume: 200-cc

🚘 Exhaust Port Volume: 70-cc

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🚘 Combustion Chamber Volume: 61.15 cc

🚘 Intake Valve diameter: 1.89 inch

🚘 Exhaust Valve diameter: 1.55 inch

🚘 Compression Ratio: 9.5:1

🚘 Selling price: $291

🚘 Compatibility: LR4, LM4, and LM7 engines.

Common Faults with 862 Heads

The 862 cylinder heads’ most frequent issue is that over time, they crack, enabling coolant to leak into the oil. Failure to address this problem could lead to serious engine damage that would be expensive to repair.

So you’ll need to replace the damaged cylinder heads to resolve the usual cracking problem. The replacement part costs between $1,500 and $2,000 from a typical car parts retailer. However, if you purchase the replacement from GM, it can be less expensive.

Are 862 Heads Good?

When pondering the question, “Are 862 heads any good?” The 862 heads are decent because, following a porting operation, they can give superior compression.

In contrast to 243 heads, the cylinder heads might not flow as well. Additionally, 826 cylinder heads are thought to be inferior to 706 heads.

The 826 cylinder head is not as advanced as some of its competitors. However, before starting a porting project, you must take all variables into account, including your budget.


Q: What are 862 Heads good for?

862 heads have good compression ability and they provide better fuel management. 862 cylinder heads are often used in racing cars.

Q: Are 706 and 862 Heads the same?

No, the 706 heads are quite superior to the 862 heads.

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Q: How do I know if I have castech heads?

The bottom right corner of the passenger section of Castech heads has a casting code (706) on it. If you check your car’s cylinder heads and you notice “706,” Castech heads are what your car has.

Castech assigns a unique identifier to each cylinder head assembly to distinguish it from the competition. Between 1999 and 2013, General Motors deployed Castech heads on its Silverado and Sierra 1500 models.

Q: What heads are on LM7?

On the GM LM7 engines are the 862 heads. Aluminum was used in the design of the cylinder heads, and the combustion chamber volume is 61cc. A cathedral-shaped inlet port and an oval outflow port are also included.

With an intake valve diameter of 1.890 inches and an exhaust valve diameter of 1.550 inches, the 826 cylinder heads on the LM7 feature a 200-cc intake runner volume and a 70-cc exhaust runner volume. Torque to Yield (TTY) bolts are also present on the cylinder heads.


Various information regarding the 862 heads has been revealed on this page. You just learned that the 862 cylinder heads are differentiated by their significantly greater compression ratio than the majority of cylinder heads.

But over time, the sand cast and the high likelihood of developing a breach between 862 heads and 243 are serious worries. The flaws may cause coolant to flow into the oil area, severely damaging the engine.

Please weigh the advantages and disadvantages of the 862 cylinder heads prior to deciding whether to port the cylinder head of your car.

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