Ultimate Chevy 4.3 V6 Performance Mod Guide

From 2014–2021, Chevrolet’s beloved Silverado 1500 and its GMC Sierra 1500 counterpart used the 4.3 liter LV3 V6 engine. Depending on the fuel and application, it produced 285-297 horsepower and 305-330 lb-ft of torque, naturally aspirated. While that’s nothing to sneeze at, when compared with the much more powerful 5.3 EcoTec3 and 6.2 EcoTec3 V8 options, it’s woefully underpowered. However, with a few Chevy 4.3 V6 performance parts, you can turn your 4.3 Silverado into a pretty formidable beast. Read on to find the best 4.3 V6 performance parts to increase horsepower and torque on your 4.3 liter LV3 V6.

Silverado 4.3 EcoTec3 Upgrade Basics

First, let’s spend a little time refreshing our knowledge of the 4.3 EcoTec3 V6. The 4.3 EcoTec3 was in production from 2014-2021, and is a 4.3 liter, direct injected, V6 engine. Chevy introduced it to replace the outgoing 4.3 Vortec V6, which had been inside the Silverados and Sierras for years. In 2021, they phased out the 4.3 EcoTec3 to focus on the larger 5.3 EcoTec3 and 6.2 EcoTec3 V8s, as well as the smaller 2.7 L3B turbo V6. 

The 4.3 EcoTec3 has an aluminum engine block and cylinder heads, and runs on either gas or E85 flex-fuel. On gas, power output is 285 horsepower and 305 lb-ft of torque. However, on E85 that jumps to 297 horsepower and 330 lb-ft of torque. Compression is quite high at 11.0:1, which is due to the direct injection and natural aspiration. The Silverado 1500 with the 4.3 had a max towing capacity of 7,900 lbs and a max payload of 2,250 lbs.

Unfortunately, the aftermarket community for the 4.3-powered Silverado and Sierras is not too large. Most companies focus on either the turbo 2.7 L3B V6 or the larger 5.3 and 6.2 EcoTec3 V8s, but there are some mods for the 4.3 EcoTec3. For the most part, you are relegated to just intake, exhaust, and tuning, but there are still gains to be had. The gains aren’t drastic, but you can definitely make the LV3 EcoTec feel much more alive after a few bolt-ons. 

The 4.3 EcoTec3 and E85

For the most gains, you will want to make sure you are always running E85 flex-fuel. E85 is a very popular new type of alternative fueling that can be used in place of gasoline in some engines. It has an effective octane rating of around ~103, meaning that it is capable of much better performance than your standard 87-93 octane gasoline that is usually available at the pump. 

In addition, E85 also has a much lower combustion temperature than gasoline, meaning the engine runs cooler and is less susceptible to things like detonation and pre-ignition. E85 is cheaper than gasoline, though you will notice your fuel economy will probably plummet, so it evens out. Some people also run a mixture of part E85 and part gasoline, to get the octane increase while still balancing out the fuel economy. 

Top Chevy 4.3 V6 Performance Parts

Our top Chevy 4.3 V6 performance parts are:

• Cold Air Intake
• Exhaust Upgrades
• Tuning

1) Chevy 4.3 V6 Cold Air Intakes

For our first Chevy 4.3 V6 performance parts recommendation we suggest looking at an upgraded cold air intake. An upgraded cold air intake gains horsepower by sucking in colder air from the side of the engine bay, while also using relatively nonrestrictive and lightweight material. To be fair, the OEM intake is technically a “cold air intake,” since it reroutes the filter away from the engine bay.

Still, an aftermarket intake will use larger piping that is less restrictive, which helps the engine suck in more air at a faster rate. This increases the rate of combustion, which adds up to more horsepower and torque coming out of the engine. Additionally, an upgraded intake will really let you hear the induction sounds from the engine, which can be very pleasing. They also make the engine bay look much better and less bland. 

Best Silverado 4.3 Intakes

For the 4.3 EcoTec3 V6, the best intakes are the K&N intake and the aFe Power Momentum GT intake. Both of these intakes will outflow the OEM intake and also use better and more heat resistant materials. They also both have airboxes with them, which help reduce intake temperatures and keep the air filter more protected from debris. The aFe Power airbox is fully closed, which will do a little better job of protecting the filter than the open airbox on the K&N.

An upgraded intake will add about 5-10 horsepower and torque by itself. They are relatively easy installs that can be done pretty quickly with only minimal tools. A cold air intake is a great way to start your 4.3 EcoTec3 build, and both the K&N and aFe Power units will perform pretty similarly to each other. 

2) 4.3 EcoTec3 Exhaust Upgrades

After upgrading the intake, for our next Chevy 4.3 V6 performance part we next suggest doing a few exhaust upgrades. There are two main parts of the Chevy 4.3 V6 exhaust to upgrade, the headers (aka exhaust manifold) and the cat-back. The headers connect directly to the cylinder heads themselves and are the most restrictive part of the exhaust. Cat-backs connect to the headers, and they contain the second half of the exhaust including the mufflers and tailpipes. 

There are two kinds of header upgrades: long-tube and short-tube. As of now, there are no long-tubes available for the 4.3 EcoTec3, making short-tubes the only option. Short tubes cover the part of the exhaust from the cylinder head to the catalytic converter. They are usually good for around 5-15 horsepower and torque on the Chevy 4.3 V6.

Cat-backs will not add any performance to the 4.3 V6, but they will however add a good amount of volume. With a cat-back, you can really hear the EcoTec3 engine much better and more aggressively. Depending on the type of mufflers, single vs dual outlets, and side vs rear exit choices, you can really customize your cat-back to make your truck unique and angry-sounding.

Best Chevy 4.3 V6 Exhaust Upgrades

For 4.3 headers, the best option are the JBA short-tube headers. These headers fit 2014–2020 4.3 EcoTec3-equipped vehicles, and will add about 5-15 horsepower and torque. They are CARB approved for 2014–2016 with an EO number, making them 50 states emissions legal. They are the only headers currently available for the EcoTec3, making the only other option pricey custom sets.

For the cat-back, the very popular Borla Exhaust makes several performance cat-backs for the Chevy 4.3 V6. Borla has long been one of the most trusted and respected names in the performance exhaust industry, and their EcoTec3 offerings look very nice. 

3) Chevy 4.3 V6 Performance Tuning

For our final Chevy 4.3 V6 performance parts recommendation, we suggest ECU tuning. ECU tuning is one of the most popular mods for any Chevy/GM truck and SUV, and the 4.3 EcoTec3 is no exception. Flash tuning involves using a handheld programmer to install new software onto your car’s engine control unit (ECU), which is what essentially controls the engine. 

By installing a new tune to your engine, things like the ignition timing, camshaft timing, fuel pressure, and variable valve timing can be optimized to increase the engine’s horsepower and torque output. In addition, if you have other mods — like an upgraded intake or headers — flash tuning will allow you to get even more gains. Usually, with tuning, you can expect to add 5-20% horsepower and torque over stock. 

Top Chevy 4.3 V6 Tuners

For custom tuning, the two top names for the 4.3 EcoTec3 are 5 Star Tuning and DiabLew tuning. Both 5 Star and DiabLew offer custom tuning for the 4.3 EcoTec3, though they use slightly different systems. Five-Star uses HP Tuners, which is a respected flash tuning company that has their own proprietary ECU flashing devices. DiabLew instead uses various Diablo-based tuning systems, which are not quite as functional but still offer solid tuning capabilities. 

Both 5 Star and DiabLew will offer solid gains for the Chevy 4.3 V6, and you can choose between optimized performance and tow tunes. That means if you use your truck mainly for towing, you can get a tune to help optimize your engine for the best low-end torque and fuel economy while towing. This makes hauling things much easier, and tunes will also help make shift points better and more conducive to performance and towing. 

Top Chevy 4.3 V6 Performance Parts FAQ