862 Heads – Everything you Should Know

862 Heads are the best when it comes to compression due to their ability to control the input and output of airflow into the cylinder heads.

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

862 engines were produced by General motors with a GEN-III Cylinder head with an aluminum build-up, they are also sand-cast making them able to yield higher compression than other cylinder heads, for example, the 799 heads

862 also comes equipped with a greater heat release rate and faster engine ignition because of the cylinder compression, it also features a high internal combustion ratio to mention a few.

Continue reading as we show you all you need to know about 862 heads upgrading to one.

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
🚘 Combustion Chamber Volume 61.55 cc
🚘 Intake Valve diameter 1.89 inch
🚘 Exhaust Valve diameter 1.55 inch
🚘 Compression Ratio 9.5:1
🚘 Selling price $300 – $750
🚘 Compatibility LR4, LM4, and LM7 engines
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Common Faults with 862 Heads

The common fault 862 cylinder heads users encounter is cracking is bound to occur on the cylinder with frequent use which in turn gives room for oil and fluid leakage which can cause severe damage if not noticed on time.

Asides from the cracks which can be resolved by replacing the damaged cylinder head, there’s no other problem. Although a replacement could cost around $750 to $2000 if you’re making a purchase from an auto dealer, it would cost less if you get it direct from general motors.

Are 862 Heads Good?

Yes, the “are 862 heads any good?” question doesn’t need to be emphasized since the cylinder head is the best when it comes to engine compression but you need to take weigh the bad and good of porting to 862 heads.

The 862 heads are inferior to the 706 heads in terms of compression and they don’t also flow well like the 243 heads because it doesn’t have other competitive features, however, depending on your car’s needs and budget, the 862 cylinder heads might be a good port for you.


Q: What are 862 Heads good for?

862 heads are a perfect choice if you’re seeking to maintain good compression ability and better fuel management. 862-cylinder heads often work well on racing cars.

Q: Are 706 and 862 Heads the same?

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

Q: What heads are on LM7?

General Motors designed LMS engines with the 862 heads installed. It featured an aluminum design and a combustion chamber volume of 61cc; including a cathedral-shaped inlet port with an oval outflow port.

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For perfection, GM installed an intake valve diameter of 1.890 inc, an exhaust valve diameter of 1.550 inc, a 70-cc exhaust volume, a 200-cc intake chamber, and TTY bolts for fit.


862 cylinder heads are known for their great compression ability which makes them suitable for racing cars, however, they have a history of cracking in the course of usage which might cause oil and fluids to leak into the engine.

It’s advisable that you check the cons and pros before you port to 862 head especially when you’re on a tight budget with long-term durability in mind.

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