862 Heads – A Detailed Overview

862 heads are some of the best cylinder heads with the capacity to deliver more compression. The cylinder head controls airflow into and out of the cylinder, as well as the deployment of fuel.

The degree of airflow and fuel deployment plays a crucial role in a vehicle’s combustion process. To that effect, every car needs a sophisticated cylinder head to gain an incredible power level for performance and efficiency.

Take some time to go through the subsequent sections to find out what you need to know about the 862 cylinder heads before performing a porting job.

862 Heads

The 862 cylinder heads are gen. III cylinder heads manufactured by GM. The cylinder heads are manufactured with aluminum. They are sand-cast, with the potential to deliver more compression than their counterparts. This is an advantage when analyzing 799 Vs. 862 heads.

The cylinder head’s compression ratio leads to increased in-cylinder pressure, a higher rate of heat discharge, and quick ignition.

A relatively high compression ratio is great for a car’s internal engine combustion process. Besides the compression ratio, the 862 cylinder heads come with more sophisticated features.

826 Heads Features/Specification

Material Aluminum
Manufacturer Part Number 12559863
Intake Port Shape Cathedral
Exhaust Port Shape D – Port
Intake Port Volume 200 cc
Exhaust Port Volume 70 cc
Combustion Chamber Volume 61.15 cc
Intake Valve Diameter 1.89 in.
Exhaust Valve Diameter 1.55 in.
Compression Ratio 9.5:1
Price $290.95
Compatibility LR4, LM4, and LM7 engines.

862 heads come on what motor

826 Heads Common Problem

The most common problem with the 862 cylinder heads is that they crack in the long run, allowing coolant to flow into the oil. Failure to fix this issue can result in severe engine damage that can be costly to repair.

So, in order to fix this common cracking issue, you’ll have to get a replacement for the cracked cylinder heads. The replacement cost is around $1,500 to $2,000 from a regular automobile parts dealer. However, it can be cheaper if you go to GM for the replacement.

Is 862 Heads Any Good?

If you are asking, “Are 862 heads any good?” The 862 heads are pretty good because they can deliver better compression after a porting job.

However, the cylinder heads may not flow well compared to 243 heads. Also, 706 heads are considered to be superior to 826 cylinder heads.

826 cylinder heads are not as sophisticated as some of their counterparts. However, you must consider all factors, including your budget, before undertaking a porting job.

FAQs

Q: Are 862 or 706 heads better?

If you’re contemplating 862 heads Vs. 706, the 862, and 706 heads are awesome vehicle cylinder heads. However, the 706 heads are more sophisticated than the 862 heads.

The 706 heads are superior to 862 heads because they are semi-permanent mold (SPM) made. Meanwhile, the 862 heads are relatively sand cast.

The semi-permanent mold (SPM) method is more consistent, even after a porting job. On the other hand, the sand cast cylinder heads (862) may not be consistent after porting the cylinder head.

If you desire a more sophisticated cylinder head for your vehicle’s engine, 706 is an incredible choice compared to 862 heads.

Q: What are the good LS heads?

LS6 was specifically designed by General Motors (GM) as the best performance. It was designed to surpass the old LS1. The LS6 did an incredible job that even the “243” casting was later recycled on LS2.

Although GM does not produce the LS2 and LS6 anymore, you can still get brand-new sophisticated bare castings for $850 from any Chevrolet high-performance parts dealers on the automotive parts market.

Q: What heads came on 4.8 LS?

The LR4 cylinder heads came on the 4.8 LS iron block engines of GM trucks. They were introduced around 1999 besides the LQ4 and LM7 truck engines which were the first set of LS engines for GM trucks.

The incredible LR4 heads were available in various GM vans, SUVs, and pickups from their inception until around 2007.

Meanwhile, if you were contemplating the period within which the LS1 or LS6 engines were introduced, the LS1 was a predecessor to LS6 and they were introduced in 1997. On the other hand, the LS6 was introduced in 2001.

Q: What heads are on LM7?

The 862 heads are on the GM’s LM7 engines. The cylinder heads are designed with aluminum materials with a 61cc combustion chamber volume. They also come with a cathedral-shaped intake port and an oval exhaust port.

The 826 cylinder heads on LM7 have an intake runner volume of 200cc, exhaust runner volume of 70cc, 1.890 in. intake valve diameter, and 1.550 in. exhaust valve diameter. The cylinder heads also have a Torque to Yield (TTY) bolt style.

Q: Are 5.3 and 6.0 heads the same?

The 5.3L engines are not the same as 6.0; hence, if you use the same cylinder heads with a cathedral-shaped intake port on both 6.0 and 5.3L engines, you will lose compression in the case of your 5.3L engine.

The loss of compression is due to the larger chamber on the cylinder heads of a 6.0L engine. 5.3L engines are completely different from 6.0L engines. 5.3L engines are 3rd generation aluminum block engines, and they have a truck manifold.

Meanwhile, 6.0L engines are 3rd generation iron block engines, and they also have an intake manifold of a truck. Another sign that distinguishes a 6.0L engine is the 6.0 stamp on the engine block.

Q: What heads do LQ9 have?

The LQ9 has 317 or 035 cylinder heads. These cylinder heads are aluminum made, with a cathedral-shaped intake port and a D-port exhaust port. The cylinder head features 210cc intake runner volume and 75cc exhaust runner volume.

Also, the cylinder heads are designed with an intake valve diameter of 2.000 in., 1.550 in. exhaust valve diameter, a combustion chamber of 71cc, and a Torque to Yield (TTY) cylinder head bolt style.

Q: What heads does a 5.3 have?

The 5.3L engines are equipped with 862 cylinder heads. The castings of cylinder heads are similar to that of 706 heads. 862 heads feature the following; 200cc intake runners, 1.890/1.550 in. valve combo, and 61cc combustion chamber volume.

The 5.3L 862 cylinder heads have a cathedral shape intake port and an oval shape exhaust port. The aluminum-made cylinder heads also feature an exhaust runner volume of 70cc. The 5.3L engine 

Q: What heads are on LQ4?

The 317 heads are designed to provide the LQ4 engines with a 9.4:1 static compression ratio. The cylinder heads perform incredibly on the LQ4 in synergy with the dished factory pistons.

The 317 cylinder heads feature the following; 71cc combustion chamber volume, cathedral shape intake port, D-port exhaust shape, 210cc intake runner volume, 75cc exhaust runner volume, 2.000 in. intake valve diameter, and 1.550 in. exhaust valve diameter.

The 317 heads are modeled similarly to the 243 heads found on LS2 or LS6. The LQ4 engines were equipped with 317 cylinder heads between 2001 and 2007. This was after they used 373 and 873 cylinder heads between 1999 and 2000.

Q: What is the difference between 821 and 823 heads?

The 821 and 823 cylinder heads are pretty much similar. However, the valves and springs are the slight distinguishing factor between the two.

The 823 rectangular port heads feature a lightweight valve combination of 2.165/1.590, as well as a peak flow of 223 cfm and 317 cfm on both the exhaust and intake, respectively. On the other hand, the 821 heads feature a valve combination of 2.180/1.600.

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

Castech heads have a casting number (706) on the lower right corner in the passenger area of the cylinder head. If you verify your vehicle’s cylinder heads and see “706” it means your vehicle has Castech heads.

Castech distinguishes its cylinder heads from their counterparts by tagging a specific number to their cylinder head assembly. General Motors used Castech heads between 1999 and 2013 on their Silverado and Sierra 1500.

Final Words

This article has exposed various details about the 862 heads. You’ve just found out that the 862 cylinder heads are distinguished by the compression ratio, which is relatively higher than most cylinder heads’ compression ratios.

However, the sand cast, as well as the high possibility of experiencing a crack, in the long run, is a major concern between 862 heads Vs. 243. The cracks can lead to coolant leaking into oil space, thereby resulting in severe engine damage.

If you intend to do a porting job on your car’s cylinder head, kindly consider the pros and cons of the 862 cylinder heads before making a final decision. After that, you can get 862 heads for sale on Amazon or any other outlets.

Osuagwu Solomon

Osuagwu Solomon is a seasoned automotive technician for the past 9 years, and a technical writer. He loves writing about auto professional repair guides, DIY repair guides, and buyer’s guide. After spending six years in the automotive workshop, he decided to impact his knowledge to people aside his domain, and he has achieved this by centering his Automotive writing skills on REPAIRS.

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