Do all NASCARs use the same motor?

No. NASCAR does not use a single, identical engine across all cars or series. In the Cup Series, Chevrolet, Ford, and Toyota each supply their own 358-cubic-inch V8s built to a common NASCAR rule set; the Xfinity Series runs to its own engine rules; and the Craftsman Truck Series uses a spec engine built by Ilmor. The result is regulated parity without one “same motor” for everyone.

How NASCAR regulates engines

NASCAR balances competition, cost, and brand identity by writing tightly defined engine rules rather than mandating one common engine across all national series. In the premier Cup Series, teams run manufacturer-specific, naturally aspirated pushrod V8s with the same displacement and performance targets. NASCAR controls peak output with airflow restrictions (tapered spacers) and track-specific rules packages, while allowing Chevy, Ford, and Toyota to pursue their own designs within the box.

What each top series runs today

Here is a concise look at the engines used in NASCAR’s major touring series, showing how they differ by category and intent.

• Cup Series (Next Gen): 358 cu in (about 5.86 L) naturally aspirated pushrod V8s with electronic fuel injection, built by each manufacturer’s engine program (Chevrolet, Ford, Toyota) to NASCAR’s common specs. Power is capped by tapered spacers and rules packages, not by a single spec engine design.
• Xfinity Series: Purpose-built NASCAR V8s following series-specific regulations. Engines are built and maintained by approved engine builders under NASCAR oversight; they are not identical to Cup or Truck engines and are not a single spec unit.
• Craftsman Truck Series: A spec engine—the Ilmor NT1—used across the field to control costs and simplify supply. This is the closest NASCAR gets to “the same motor” in a top national series.
• ARCA Menards Series (NASCAR-sanctioned): Predominantly uses the Ilmor 396 spec engine, with legacy “open” engines permitted under balancing measures.
• Regional/International series (e.g., Whelen Modified Tour, Euro Series, Mexico Series): Run engines tailored to their formats and rules, which can differ significantly from the national stock-car V8s.

Taken together, the picture is mixed: Cup protects manufacturer identity within tight limits, Trucks lean on a spec powerplant for cost control, and other series apply their own blends of “open” and spec approaches.

Inside the NASCAR Cup Series: the engines aren’t identical

Even within the Cup Series, engines are not the same. All must be 358 cu in pushrod V8s on standardized fuel and electronics, but each manufacturer designs and develops its own approved package. NASCAR then equalizes performance with intake spacers and rules packages that target specific horsepower windows (for example, reduced power on superspeedways), aiming for parity without erasing brand differences.

Who actually builds the Cup engines?

A few powerhouse programs supply the majority of the field under their manufacturer banners.

• Chevrolet: Hendrick Motorsports Engines (and aligned partners) produce the Chevy “R07”-family Cup engines.
• Ford: Roush Yates Engines develops and supplies Ford’s “FR9”-family Cup engines.
• Toyota: Toyota Racing Development (TRD), in partnership with Joe Gibbs Racing’s engine group, supplies the Toyota Cup engines.

These engines share displacement and broad architecture but differ in internal design details, development paths, and supplier ecosystems, which is why they are not literally the same motor.

What NASCAR standardizes—and what it doesn’t

NASCAR carefully specifies some elements to keep performance in check while leaving room for manufacturer identity and engineering.

• Standardized: Displacement (358 cu in for Cup), fuel type (Sunoco E15 in Cup), induction type (naturally aspirated), basic architecture (pushrod V8 in Cup), ECU oversight, and intake restrictors/tapered spacers to hit horsepower targets by track type.
• Not standardized: The exact internal design of each manufacturer’s engine (within the rules), development strategies, and the engine programs used in other series (e.g., Ilmor spec engines in Trucks and ARCA versus “open” builds in Cup and Xfinity).

This split approach allows NASCAR to maintain close racing and cost discipline without mandating a single, uniform engine across the sport.

Why NASCAR doesn’t use one engine everywhere

Three practical reasons drive the policy: competitive identity (manufacturers want their own engines), cost management (spec engines in some series keep budgets sane), and technical fairness (rules and spacers keep performance clustered even when engines aren’t identical). This hybrid model supports both factory involvement at the top level and accessibility in development series.

Bottom line

No, not all NASCARs use the same motor. Cup cars use manufacturer-built engines within a common rule set, Xfinity has its own approved engine landscape, and the Truck Series relies on a spec Ilmor engine. The details vary by series, but NASCAR’s rules keep performance tightly grouped so the racing—not the differences in engines—defines the show.

Summary

NASCAR does not mandate a single engine across all cars. Cup teams run manufacturer-specific 358 cu in V8s to uniform rules, Xfinity uses series-regulated V8s from approved builders, and Trucks use a spec Ilmor NT1. NASCAR standardizes key parameters and uses spacers and rules packages to equalize performance while preserving brand identity and controlling costs.

Are all the engines the same in NASCAR?

No, not all NASCAR engines are the same; although they must conform to NASCAR’s specifications for displacement (358 cubic inches), V8 configuration, and pushrod design, the specific designs for engine blocks, cylinder heads, and intake manifolds can differ among manufacturers like Ford, Chevrolet, and Toyota. These differences allow manufacturers to develop unique engines for competition while still adhering to the sport’s technical regulations.
 
What is standardized:

• Displacement: All NASCAR engines are limited to 358 cubic inches (approximately 5.8 liters). 
• Configuration: They must be naturally aspirated V8 engines. 
• Valvetrain: A pushrod (overhead valve) design is mandated, rather than modern overhead cam designs. 
• Compression Ratio: A 12:1 compression ratio is required. 

What differs between manufacturers:

• Engine Architecture: Ford, Chevrolet, and Toyota each submit their own designs for approval, leading to differences in their specific engine components. 
• Components: The intake manifolds, cylinder heads, and engine blocks can all be different for each manufacturer. 
• Engine Development: Within each manufacturer, engine development can continue, with different racing alliances (like Hendrick and Childress for Chevrolet) building engines based on their own specific designs. 

Why differences are allowed:

• Not a Spec Series: NASCAR is not a spec series, meaning that engine specifications are not completely identical for all competitors. 
• Manufacturer Competition: Allowing variations encourages different manufacturers to compete and innovate, contributing to the sport’s excitement. 
• NASCAR Oversight: NASCAR tightly regulates these differences, ensuring that no single manufacturer gains an unfair advantage through engine design. 

Why is Dodge not allowed in NASCAR?

Ultimately, Dodge chose to withdraw from NASCAR, citing the inability to secure a partnership with a team that met its high standards for competitiveness and technological innovation.

What engine was banned from NASCAR?

NASCAR has banned several engines throughout its history, but two prominent examples are the Ford 427 SOHC Cammer due to its advanced single overhead camshaft design, and the Chrysler 426 Hemi because of its overwhelming dominance, which led to fears of uncompetitiveness. Additionally, the engine in the 1969 Chevrolet Corvette Grand Sport was also banned, not due to rule-breaking, but because GM corporate policy prohibited its factory entry into the competition.
 
The Ford 427 SOHC Cammer

• What it was: A high-performance V8 engine with single overhead camshafts (SOHC) and electronic fuel injection, designed to compete with Chrysler’s Hemi. 
• Why it was banned: NASCAR banned overhead camshaft (OHC) engines, making the Cammer ineligible for stock car competition. 
• Aftermath: Ford shifted its focus to drag racing, where the engine became a legendary and dominant force. 

This video explains why the Ford 427 SOHC Cammer was banned from NASCAR: 38sRare Car StorysYouTube · Feb 12, 2025
The Chrysler 426 Hemi 

• What it was: An incredibly powerful and compact engine that quickly achieved a high level of success in NASCAR. 
• Why it was banned: The Hemi’s dominant performance was so overwhelming that it was banned to “level the playing field” and restore unpredictability to races. 
• Aftermath: The ban wasn’t permanent, and the Hemi was allowed back into NASCAR after rules were revised to ensure its availability in production cars. 

You can watch this video to learn about the history of Hemi engines in NASCAR: 55s4 Wheels ChroniclesYouTube · Sep 23, 2023
Other Notable Banned Engines 

• Smokey Yunick’s “Mystery Motor”: This advanced Chevrolet engine was banned by NASCAR before it ever raced, though not for breaking rules but due to the potential for it to completely rewrite the sport’s history.

What brand engines do Nascars use?

NASCAR engines are built by manufacturer-affiliated entities, with Ford engines produced by Roush Yates, Chevrolet engines by Hendrick Motorsports and ECR Engines, and Toyota engines by Toyota Racing Development (TRD). While each manufacturer submits engine designs for NASCAR’s approval, these engines are custom-built by these specialized entities for competitive use within the NASCAR regulations.
 
Manufacturer-Specific Engine Builders

• Ford: Engines are exclusively built by Roush Yates Engines. 
• Chevrolet: Engines are developed and built through a partnership between Hendrick Motorsports and ECR Engines. 
• Toyota: Engines are developed by Toyota Racing Development (TRD). 

How the Engines Are Made

• NASCAR Approval: Each manufacturer (Ford, Chevrolet, and Toyota) submits its engine design to NASCAR for approval, ensuring it meets the series’ specifications. 
• Customization: Once approved, these specific engine components (block, cylinder heads, etc.) are used by the respective manufacturers. 
• Team-Specific Operations: Manufacturers then work with their teams to build these engines. For instance, Hendrick Motorsports builds Chevrolet engines for many Chevy teams, while ECR Engines provides engines for other partners.