Why Are NASCAR Engines So Powerful?

It is easy to assume NASCAR engines are so powerful because they can withstand high speeds for a 300 to 500-mile race time and again. NASCAR’s engines are specifically designed for the race track. But you might be wondering the specific reasons why NASCAR engines are so powerful. 

NASCAR engines are so powerful because of the way they are constructed and tuned. They are 5.9-liter V8 engines with up to 670 horsepower. Teams can also fine-tune them within NASCAR’s specs, which gives them more power in certain areas of a race track, depending on the race.  

Below, we will unveil who makes NASCAR engines and how they are different from those seen in your traditional road car. We will also discuss how much power NASCAR’s Next Gen engine has, and how manufacturers make NASCAR engines so powerful. 

Who Makes NASCAR Engines?

NASCAR engines come straight from the 3 manufacturers: Chevrolet, Ford, and Toyota. NASCAR has strict specs when it comes to engine building. NASCAR teams and manufacturers want a sense of brand identity with their engines, so only use engines from those 3 manufacturers.

While the Next Gen car changed NASCAR’s landscape in many areas, only the horsepower packages and transmission changed from the Generation 6 model. The Gen 6 design had engines that clocked in at 550 horsepower, although they did use 750 horsepower engines in the past, too. 

The horsepower packages are specs that NASCAR manufacturers must follow. Also, NASCAR requires an engine that is naturally aspirated with a displacement of 358 cubic inches. If NASCAR’s specs change, all three manufacturers must conform to those changes. 

NASCAR also switched up the transmission. They did away with the 4-speed transmission and gearbox. In its place is a 5-speed sequential transmission. This simplified transmission allows the driver to push down one notch to shift down and to pull back a notch to shift up. 

NASCAR Must Approve Engine Designs

Since NASCAR is not a spec series but they want to keep their playing field even, manufacturers cannot just create a new engine and send it to their teams. Instead, they must submit a design to NASCAR for approval. Once approved, teams can then build their engines. 

If a new manufacturer enters NASCAR, they would be subject to the same regulations. Also, if a manufacturer like Dodge wished to re-enter NASCAR, they would also need to submit a custom design that fits NASCAR’s specs. 

How Much Power Does A NASCAR Engine Have?

NASCAR engines have up to 670 horsepower in their current configuration. NASCAR’s engines only need to be powerful enough for the cars to reach and maintain a specific speed. Therefore, the power of a NASCAR car’s engine varies a lot, especially between longer and shorter tracks.

The Next Gen car is a fine example of this. They come with far more downforce than their predecessors, the Generation 6. So when NASCAR designed the Next Gen, they realized their horsepower package used with the Generation 6 car would not cut it. 

Generally, the Generation 6 design commonly used engines that ran at 550 horsepower, which dropped to 410 horsepower at superspeedways. NASCAR also switched between 550 at larger tracks and 750 at short tracks and road courses earlier in the Generation 6’s life span. 

It wasn’t until 2019 that NASCAR opted for the 550 package at most tracks since they allowed for more entertaining races. While NASCAR tested the 550 package with their Next Gen cars, they found that the cars’ handling was off. 

Slower Speeds

Further, the 550 package produced slower speeds for the Next Gen car when compared to the Generation 6 model. In late 2021 they were more than 2 seconds off of the fastest laps. 

So to improve the handling and the speed, NASCAR bumped up the horsepower to 670 on every track except for Daytona and Talladega, in which they used a 510 horsepower package. 

Another reason NASCAR needed to up the horsepower package for the Next Gen car was because of increased downforce and aerodynamics. The Next Gen design was said to include up to 1,000 more pounds of downforce, which further necessitated a more powerful engine. 

When NASCAR went with the 670 horsepower package, their drivers reached speeds of 180 miles per hour (mph) and higher during testing sessions at the Charlotte Motor Speedway. In some cases, they traveled even faster than the Generation 6 car. 

How Do NASCAR Engines Produce So Much Power?

The 3 main reasons NASCAR engines produce so much power are fuel composition, tuning, and the way manufacturers construct these powerful engines. These 3 factors combine to make engines that can put out around 670 horsepower for the Next Gen cars. 

While there are cases where NASCAR engines may not have an incredibly higher amount of horsepower than some road cars, they possess more horsepower than most. Plus, manufacturers must build these engines so they can maintain high speeds throughout a 300-500 mile event. 

You may be wondering how Toyota, Chevrolet, and Ford accomplish this. One thing you must remember is that NASCAR engines are not produced on traditional assembly lines. Instead, they are built specifically for NASCAR, which is one of several reasons why NASCAR cars are not truly stock cars. 

Fuel Composition

NASCAR cars do not run on the same type of fuel as your street car. Instead, they use a special type of fuel provided by Sunoco that is called Sunoco Green E15. This contains a 98 octane rating and it comprises 15 percent ethanol. 

Most road cars use 88 octane, meaning they cannot withstand compression before detonation to the same length as a NASCAR car, given its lower octane rating. The higher the rating, the better a car can withstand detonation. Such a high level of resistance makes the car more explosive


NASCAR engines are capable of running higher than their targeted 670 horsepower. However, NASCAR teams use tapered spacers to keep cars from going over their targeted horsepower. This horsepower is actually lower for superspeedways like Daytona and Talladega, being set to just 510. 

They can tune their engines specifically to the track they are racing at if they remain within NASCAR’s specs. For example, short tracks require more power and torque despite lower speeds, while road courses, given so many turns, require more acceleration. 

This is the same 670 horsepower engine being fine-tuned. The difference, however, is that teams tune it to where they feel the car needs the power to be at its highest. This process may even involve tuning each cylinder. Each NASCAR team’s engineers use computer software to make this endeavor possible. 


When you compare a NASCAR engine to that of your road car, you’re going to see staunch differences. These engines contain thicker cylinder walls and they are often larger displacement-wise, at 5.9 liters, or 358 cubic inches. This large displacement alone gives a NASCAR engine immense power

Thicker cylinder walls further provide the engine greater power thanks to increased compression and heat dissipation. Finally, the overall construction gives these engines more shelf life at such high speeds than that of a road car. 

How Are NASCAR Engines Different From Street Car Engines?

There are a few noticeable differences between NASCAR engines and street car engines. However, you might be shocked as to how closely the Camaro and Mustang engines come to the NASCAR Next Gen engines.

You probably know that the Next Gen NASCAR cars closely resemble their production car counterparts much more than the older models. Take one look at the Chevy Camaros, Ford Mustangs, and Toyota Camrys gracing the track, and you might mistake their bodies for production cars. 

Since NASCAR engines are built specifically for NASCAR and those of street legal Camaros, Mustangs, and Camrys are built on production lines, there are still noticeable differences between NASCAR engines and street car engines. 

Chevy Camaro

The 2022 ZL1 has a V8 just like its NASCAR counterpart. However, they have a displacement of 6.2 liters and 6-speed manual transmission, so there is more to it than the NASCAR engine. It also has 650 horsepower, just 20 below NASCAR’s targeted 670

Ford Mustang

The 2022 GT 500 has a smaller engine than its NASCAR equivalent, with its V-8 engine clocking in at just 5.2 liters. They also have a smaller, 7-speed dual clutch transmission. But at 760 horsepower, the engine is stronger than NASCAR’s targeted 670. 

Toyota Camry

The 2022 TRD has just a 3.5-liter V-6 engine, so it is substantially smaller and less powerful than NASCAR’s Camrys. Its 301 horsepower is also significantly less than the Camrys racing around the track. It also has an 8-speed and not a 5-speed sequential transmission. 

Final Thoughts

NASCAR engines are so powerful (outputting around 670 HP) because they are larger than that of your average production car and are designed specifically for racing in NASCAR. These engines are sent directly to NASCAR teams, who build their cars from the ground up inside shops.