799 Vs 243 Heads: Are They The Same?

A car’s cylinder head is an excellent part. It significantly contributes to the engine’s exceptional performance.

Some cylinder heads, however, have an architecture that reduces the engine’s ability to produce power.

Conversely, certain cylinder heads have the best architecture and produce excellent power output with more horsepower.

Let’s examine the 799 vs 243 heads and see why porting would be a good solution for them. Spend the next three minutes reading this article from beginning to end.

What Are 799 Heads? 

799 vs 243 heads

Some of the newest cylinder heads available on the car components market are 799 heads.

They are the ideal option for a porting job since they provide good performance with more horsepower.

The most recent model uses the semi-permanent mold technique to create these 799 heads. The aluminum heads of the 799 heads can endure high temperatures.

Aluminum is a great material since it is strong but lightweight.

 In terms of triangle casting, they are comparable to 2004 LS2 heads, but unlike the 243 heads, they don’t need to be cleaned.

Users of 799 heads can employ vacuum and pressure testing to check the valve seating of the 799 cylinder heads. It aids in ensuring the dependability of the cylinder head’s channel.

Truck engines with 5.3L and 4.8L displacements were the LS engines built with 799 heads.

The LS 799 heads‘ advanced architecture and cathedral-shaped exhaust port enabled them to provide remarkable truck engine performance.

What Are 243 Heads? 

The 243 heads from GM are third-generation cylinder heads designed for performance applications, V8 trucks, SUVs, and vans. They are frequently known as LS6 heads.

The 243 heads have redesigned intake ports and D-shaped exhaust openings, providing exceptional performance and efficiency. They are cast from an aluminum alloy.

It was briefly used on the C5 Corvette and the first-generation Cadillac CTS-V before being ported to the LQ4 and LQ9 to meet truck needs.

The ls6 engine block debuted in 2000 or 2001 and was the first to include 243 heads. The LS1 and LS2 both included 241 and 243 as standard equipment.

Undoubtedly, anyone can swap out any cathedral port head made by GM without performing any tuning. They are also simple to bolt on.

Even though all valve springs have the same purpose, some operate well and feel good. The 243 heads will give you that extra push and improve your vehicle’s performance.

799 Vs 243 Heads: Are They The Same?

ls 799 heads

They are identical, to put it simply. They can both be used interchangeably.

Both have slight variations from the factory, but because they share the same port architecture, working them over practically follows the same procedure.


The 243s are investment cast, whereas the 799s are sand cast; the heads are identical in design.

The 243 heads’ superior casting, better flow, fantastic design, and comparatively great marginal gain compared to its pricing are meant to offer an additional boost level and increased performance with superior strength.

You can get 799 heads for $300 and have them ported if you shop around and find a good bargain. To recoup some of that money, you might sell your stock heads for $100 to $150.

Not all 243 heads have hollow stem intake valve size and sodium-filled exhaust valve jobs. They are more expensive because of this. The majority, however, features sturdy stainless steel valves.


The 243 heads have smaller valves and a slightly larger combustion chamber design than the 799 heads, with a greater compression ratio of 64.45cc.

They share the same port design, but one has a 10cc greater intake port volume.

The changes are visible if you look at the valve diameter. I’ve seen factory engines with heads with two different casting numbers.

I discovered a 799 on one side and a 243 on the other of the heads of a 4th Gen 5.3 I own. The size of the valve is everything.

Setting up some casting numbers for two different bore sizes is possible.

Compression Ratio

The compression ratio of a car measures how much air is pressed down for each kilogram of fuel burnt. This measurement impacts the effectiveness, power, and effectiveness of a vehicle.

The intake, spark plugs, and exhaust valves on the 243 heads are opened and closed by 1.7-ratio rockers. The greatest compression ratio achieved with the 799 cylinder heads is 0.075.

The preference for 799 heads over 243 heads is more common among owners of normally aspirated engines.

Combustion Chamber

The combustion chamber size is the same for 799 and 243 heads. The 243s have a steel chamber volume, while the 799 has a sand combustion chamber diameter tool.

Therefore, if not ported, the 243 may be smoother than the 799s. Similar to contrasting the earlier LS 1 heads with the smoother 241s.

799 Vs 243 Heads: Which Is Better?

243 vs 799 heads

Whether 799 heads are superior to 243 heads is hotly contested. You should search for cylinder heads that meet your desired flow and compression requirements.

While each pair of GM LS head cylinder heads will have advantages and disadvantages of their own, they are both highly potent heads to install on your GM engine.

Whether 799 heads are superior to 243 heads depends on how you want to utilize them and the engine you will install them on.

The 799 heads are superior to the 243 heads for automobiles because it is more efficient. Because it has a larger capacity, the Chevy 799 heads are better than the 243 heads.

Most cars with 4 or 6 cylinders can use the 243 heads. Compared to its rival, the 799 cylinder head, it has more ports for greater air intake and exhaust flow, resulting in higher power output.


Are 799 Heads Good?

The 799 heads are excellent, of course. The 799 heads presented plenty of flow. They provide one of the best flows available from premium cylinder heads in the automobile sector.

The cylinder heads’ combustion chamber is smaller, resulting in higher compression and horsepower.

What Is Better Than 243 Heads?

Based on head flow, standard LS 243 heads may generate about 5% more power level than factory LS1 heads.

However, the LQ9-LQ5 heads, cast numbers 317 and 873, are cheaper and accessible in a wide range if you’re looking for a good turbocharger or supercharger head.

Although they employ LS6 ports, those engines’ larger 71 cc chamber diameter offers the little compression drop needed for forced induction.

What Are The Most Powerful LS Heads?

The strongest small block engine in 3rd-generation cylinder heads is the LS6. An upgraded version of the original LS1 engines, this 5.7 l engine has more power.

The body of this amazing cylinder head is made of aluminum.

These engines have a high horsepower capacity and are amenable to modifications like turbochargers, superchargers, high-flow cylinder heads, intake structures, cams, and nitrous oxide.

Better heads, a more aggressive cam, and a significantly enhanced intake manifold were added to the LS6.

The most aggressive cam that GM produced for cathedral port-headed LS engines is the LS6 cam.


Even though cylinder heads are an essential part of the engine and one of its most expensive components, knowing the differences between 243 vs. 799 heads will help you understand your car better.

The increases you’ll get on the 799 vs 243 heads, though, can be remarkable if you intend to adjust your heads.

Leave a Comment