Due to their ability to regulate the input and output of airflow into the cylinder heads, 862 heads are optimal for compression.
If you need a complex cylinder head with enough power to boost your vehicle’s performance and efficiency, go for the 862 cylinder head.
General Motors produced 862 engines 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 |
Common Faults with 862 Heads
The common fault 862 cylinder heads users encounter is that cracking is bound to occur on the cylinder with frequent use, which gives room for oil and fluid leakage, which can cause severe damage if not noticed on time.
Aside 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 purchasing from an auto dealer, it would cost less if you get it directly 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 for engine compression, but you need to weigh the bad and good of porting to 862 charges.
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.
FAQs
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 pretty 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.
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.
Conclusion
862 cylinder heads are known for their excellent compression ability, which makes them suitable for racing cars. However, they have a history of cracking during usage, which might cause oil and fluids to leak into the engine.
You should 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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