243 Heads: All About 243 LS Heads & Their Application

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Initially, General Motors made seven different versions of the LS engine, and the majority of them had varying heads. The head names are indicated by the stamp on the valve cover that shows the three-digit head number.

The 243 heads were put on the LS6 engines. Initially, the heads were made for C5 Corvettes, used from 2001 to 2006. The LS6 was also used in some Camaros and Pontiac GTOs.

The 243 heads are cast out of aluminum alloy, and they feature larger intake and exhaust ports compared to other heads. They also have higher-lift camshafts, which allows for greater airflow.

The 243 heads come with 1.7-ratio rockers responsible for opening and closing the intake and exhaust valves. The configuration is different from the 1.8 ratios found on most other LS heads. The main benefit of this is that it allows for greater lift, which results in more airflow and more power.

If you want to buy 243 LS heads, Allied Motor Parts is just the place for it. Get in touch today.

Highlighting Features of 243 LS Heads

The LS6 had a stiff valve train coupled with an aggressive camshaft that made it perfect for the Corvettes at the time. Ported 243 heads can still be used today due to their many highlighting features.

Cylinder Block

The cylinder block is the foundation of the engine. It's where the pistons, rods, and crankshaft are housed. The block is also where you'll find the oil pan and water jacket.

The 243 heads were initially designed for the LS6 engine, which had a smaller 4.8L displacement. The LS6 cylinder block has many similarities with the V8, such as a 4.4-inch bore center and a 90-degree angle.

Rotating Assembly

The assembly of an engine that rotates is called the rotating assembly. It consists of the crankshaft, connecting rods, and pistons.

The LS6's rotating assembly includes a forged steel crankshaft and powder metal connecting rods. The pistons are made from cast aluminum and have a hyper eutectic design. As a result, the LS6's stroke is 3.62 inches shorter than the V8's 4-inch stroke. It helps to create more torque at lower RPMs.

Meanwhile, the compression ratio of the LS6 is 10:1, which is higher than the V8's 9.6:1 compression ratio. As a result, it helps the engine to produce more power.

Cylinder Heads

The cylinder heads are responsible for housing the intake and exhaust valves. They also have combustion chambers where the air/fuel mixture is combusted.

The 243 cylinder heads are made of aluminum with steel intake. The exhaust valves are at a 15-degree angle to maximize airflow. Other components of the 243 cylinder heads are roller-pivot rocker arms and beehive valve springs.

  • Roller-Pivot Rocker Arms: A rocker arm is a lever that transfers motion from the camshaft to the valves. The LS6's rocker arms are made of investment-cast nodular iron, with a 1.7:1 ratio. They also have needle roller bearings to minimize friction.
  • Beehive Valve Springs: The beehive valve springs increase valve train stability at high RPMs. They are made of chrome silicone, and they can handle a lift of up to 0.550 inches.

Engine Management

The engine management system is responsible for controlling the air/fuel mixture, ignition timing, and idle speed. It does this by using sensors that monitor various engine parameters.

The LS6 engine is managed by the Engine Control Module (ECM). The ECM uses information from the following sensors:

  • Crankshaft position sensor
  • Throttle position sensor
  • Mass airflow sensor
  • Oxygen sensor
  • Coolant temperature sensor

The ECM uses this information to make real-time adjustments to the air/fuel mixture and ignition timing. Thus, it helps optimize engine performance and fuel economy.

Camshaft Design

The camshaft is responsible for opening and closing the intake and exhaust valves. It also controls the timing of these events.

The LS6 camshaft is made of forged steel, and it has a duration of 204 degrees. The lift is 0.480 inches, and the lobe separation angle is 112 degrees. The camshaft design is similar to 241 heads.

Intake Manifold

The intake manifold is responsible for delivering the air/fuel mixture to the cylinders. It has a cast aluminum build and a runner length of 12 inches.

The intake manifold has a lower plenum and an upper plenum. The lower plenum is where the air enters the manifold, while the upper plenum is where the air/fuel mixture is distributed to the cylinders.

The intake manifold in 243 LS heads has a 30-pound-per-hour fuel injector. The results from this intake manifold configuration later became the standard for LS1 243 heads due to their effectiveness.

24x Ignition System

All LS6 engines have a 24x crankshaft reluctor wheel. The wheel maintains a consistent relationship between the crankshaft position and the ECM. As a result, the ECM can provide accurate ignition timing control.

The LS6 also has a coil-near-plug ignition system. It means that there is one coil for each spark plug. The coil-near-plug ignition system is more efficient than the conventional distributor ignition system. As a result, it helps to improve engine performance and fuel economy.

Exhaust System

The exhaust system removes the combustion gases from the cylinders. It consists of the following parts:

  • Exhaust manifold
  • Catalytic converter
  • Muffler

The LS6 exhaust manifold is made of cast iron. It has a cross-over design, and it is connected to the catalytic converter with a stainless steel pipe. The catalytic converter is responsible for reducing emissions.

The muffler is located at the end of the exhaust system and helps in noise reduction. The LS6 engines have the same exhaust manifolds as their LS1 counterparts.

Difference Between LS and LS1

If you're planning to buy LSO 243 heads, you should know how they differ from the LS configuration. There are three main differences between both engines.

  • Port Shape: The port shape of both heads is different. The LS6 has a D-shaped exhaust that facilitates a better flow. Meanwhile, the 241s have over-shaped exhausts that offer an intake flow of 200 cfm.
  • Valve System: The ported 243 heads have a sodium-filled, hollow valve system. It lowers the inertia of the valve train. However, this design is lacking in the 241 heads.
  • Combustion Chamber: The combustion chamber in 243 heads is 65cc while 241s has a 67cc combustion chamber. Due to this, the 243 heads have a higher compression ratio.

When looking for the ideal heads to pair with your LS engine, it is important to consider the airflow potential, port shape, and valve system. For example, the 243 heads offer better airflow, port shape, and valve system than 241s.

Purchasing 243 Heads

Purchasing 243 heads can be daunting because many vendors sell fake or used parts. Therefore, it is vital to buy your heads from a reputable vendor to ensure that you're getting a quality product.

Moreover, make sure you compare the head types to find the best one for your needs. At Allied Motor Parts, we provide 243 heads for sale. So whether you're looking for CNC ported 243 heads or Chevy 243 heads, we've got them all. We also offer a wide range of other LS performance parts.

Allied Motor Parts is the leading provider of LS performance parts. We have a team of experts that can help you choose the correct parts for your vehicle. Contact us today to learn more about our products and services.

Related Products of 243 Cylinder Heads:

CNC Ported LS1/LS6 243/799 Cylinder Heads .650 Springs 2.02/1.59 Valves PAIR 

Chevy Cylinder Head LS1/LS6 243/799, Year:97-04

Chevy Cylinder Head LS1/LS6 243/799 - PAIR, Year:97-04

NEW CNC Ported LS1/LS6 Cylinder Heads .650 Springs 2.02/1.59 Valves PAIR

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