If you like playing around with factory-installed cylinder heads with aftermarket ones, you have many options to explore. But as for me, I tried swapping my 799 cylinder head with 243 to see if it changed anything in my Chevy. And will you believe it if I tell you that the result caught me off-guard?
If you want to know why, then I suggest you read this 799 vs. 243 heads comparison article. I have discussed pretty much everything regarding them here.
What Are Cylinder Heads?
If you are new to this comparison game, you need to know what a cylinder head is and how it works in a vehicle. So pay attention here.
A cylinder head is a vehicle’s internal part that is installed on top of the engine block. It contains several parts, such as spark plugs, valves, fuel injectors, etc. Its main job is to veal the combustion chamber and manage the air-fuel mixture that goes through from the cylinder to the engine.
As you can tell, the cylinder head plays one of the vital and most crucial roles when determining the performance of any vehicle engine. That is why it is essential to choose the right cylinder head when you are replacing the old one.
799 Vs 243 Heads: Specification Comparison Table
Plate Cast (Smooth Texture)
799 Vs 243 Heads: Main Feature Comparison
Though the 799 and 243 cylinder heads are similar in many ways, you can see from the table above that there are slight differences as well. But does it mean they perform differently? Well, the only way to find that is to compare the important features first. In the following part, I have compared some of such features to find similarities and differences.
If you are hearing that both 799 and 243 heads are the same, here is where you will spot the main difference. The 799 cylinder heads have a sand casting and finish, which makes them rough. On the other hand, the 243 heads have a metal casting and finish, which makes them smoother than sand casting ones.
I didn’t notice that myself at first. However, when browsing through various forums for research, I came across this information. And when I went to buy the heads and compared them, I noticed it was true. But does the casting difference affect their performance? Well, I will discuss more on that later.
Compatible Engine Type
Anyone who is considering getting either the 799 or 243-cylinder head needs to know about their engine compatibility to make sure they offer their 100%. When trying to test them, I discovered the 799 head is compatible with 4.8L, 5.3L, 5.7L, or 6.0L truck engines. On the other hand, the number is slightly low with 243 cylinder heads. It is compatible with 5.3L, 5.7L, 6.0L truck engines.
The 799 heads were generally made for the GMC Sierra, Chevrolet Silverado, and various other LS6 trucks. And the 243 heads are more compatible with Chevrolet Corvette Z06, V8 trucks, SUVs, vans, etc. Nevertheless, they are both known as LS6 truck heads because of their compatibility.
Material And Weight
Both 799 and 243 heads are made of high-grade aluminum. The good thing about aluminum is that it makes the heads lightweight and very durable. On top of that, both of them weigh 26 lbs, which means installing them will not overburden the vehicle and keep its performance steady.
Intake And Exhaust Port Shape
There is no difference between the 799 and 243 intake and exhaust port shape. Both have a cathedral intake port and a D-port exhaust. These port designs are known for their ability to increase air and gas flow.
Intake And Exhaust Valve Size
With a 2-inch intake valve and a 1.55-inch exhaust valve sizes, both 799 and 243 go head to head when it comes to a better response. Besides, they allow more fuel combustion and it automatically reduces emissions.
Intake And Exhaust Port Volume
The intake and exhaust port volumes of the 799 head are 209 cc and 74 cc. On the other hand, the port volumes of the 243 head are 210 cc and 75 cc. Due to having a larger port volume, the 243 head helps more air and fuel enter the engine, which automatically ensures more torque and horsepower.
The 799 cylinder heads come with a 64 cc combustion chamber, whereas the 243 comes with a 65 cc combustion chamber. While the difference seems ignorable, it is a known fact that a smaller combustion chamber will create more compression and improve vehicle performance.
Pros And Cons Of 799 Heads
Pros And Cons Of 243 Heads
799 Vs 243 Heads: Performance Comparison
As you have learned so far, the 799 and 243 heads are nearly identical because of their similar design and constructions. But you can never know exactly what to expect unless you install them and ride the vehicle with them. So I took my turns with both and here is what I found.
The way they performed was pretty similar. But one thing that makes them different is their casting, which eventually affects their performance and power level. As I mentioned a few times already the 799 head comes with a rough sand casting whereas the 243 comes with a smoother metal casting.
Because of this difference, 243 head offers a more balanced ride as its smooth finish ensures better airflow. On the other hand, 799 head did ensure a powerful ride with a maximum of 25 HP. However, it eventually affected the vehicle’s fuel efficiency. But I did not have any such problem with the 243 head.
Also, remember how I mentioned that having a smaller combustion chamber creates better compression? Since the 799 and 243 heads don’t really have much difference in combustion chamber size, I barely noticed any difference because of that. In fact, the 243 head was already better in many ways that it seemed more suitable for my trucks.
Can I Replace 799 Head With 243 Head?
Since many people think the 799 cylinder head and 243 cylinder head are different, it is natural to wonder if they are interchangeable. The answer is yes, you can.
Since they share very similar features, sizes, and dimensions, you can easily replace them with one another. In fact, I have known users who installed 799 head at one end and 243 at another. But will that affect the vehicle’s performance?
Well, the answer depends on the vehicle’s compatibility and what you expected from the cylinder heads. However, I always recommend using the same cylinder heads, and this is no exception.
Aftermarket Head vs. 799 Head Comparison
When I took out both 799 and 243 heads in front of me, I could hardly tell which one was which. The similarity is so uncanny that it’s really hard to tell they are different cylinder heads. And as you have seen in the table above, they are indeed similar in many ways. As a result, when it comes to performance comparison, the 799 vs 243 heads don’t really show a big difference.
Yet, depending on your vehicle type, cylinder head compatibility, installation, and location will have an impact on how they perform. So I always suggest users try both and experience the differences themselves. Because the best cylinder head is the one that lives up to the user’s expectations.