Is a 360 magnum a big block?

The 360 Magnum is not a big-block. It is Mopar’s small-block V8, part of the Magnum family that includes other 318/360-era engines, while big-block Mopar engines live in a separate RB/B-block line with larger physical dimensions.

In this article, we’ll unpack what that distinction means for enthusiasts and owners, explain how Mopar classifies engine families, and explore practical implications for restoration, swaps, and performance projects. We’ll also offer tips on identifying the engine you’re looking at and understanding the terminology that often causes confusion in car culture.

What distinguishes big-block from small-block in Mopar nomenclature

To understand the distinction, it helps to know that “big-block” and “small-block” refer to distinct families with different block design, bore spacing, and mounting patterns. The 360 Magnum sits on the small-block side, while the classic Mopar big-blocks belong to the RB/B-block family and are physically larger and heavier.

The following list highlights the core differences you’re most likely to encounter when comparing a 360 Magnum to Mopar big-block engines:

• Block size and overall dimensions: Big-blocks are physically larger, taller, and heavier than small-blocks, which affects fitment in engine bays and weight distribution.


• Displacement range and internal design: Small-blocks like the Magnum line typically cover up to around 360 cubic inches (and related variants), while big-blocks run from roughly the high-300s to 440 cubic inches and beyond in many configurations.


• Block family and architecture: The 360 Magnum is part of Mopar’s small-block lineage (Magnum/LA), whereas big-blocks belong to the RB/B-block family with a different casting family and mounting geometry.


• Mounting patterns and bellhousing compatibility: Small-block and big-block engines use different bellhousing patterns and mounting pads, which can complicate swaps without adapters or aftermarket fabrication.


• Applications and era: Small-block Magnums were common in mid-size cars and light trucks in the 1990s–early 2000s, while big-block Mopars found homes in full-size cars and heavy-duty trucks and muscle-era applications.

Collectively, these distinctions explain why the 360 Magnum is categorized as a small-block and why it’s not considered a big-block in Mopar terminology.

The Magnum engine family and where the 360 fits

The Magnum name signaled a refreshed generation of Mopar small-block engines introduced in the late 1980s and carried into the 1990s and early 2000s. The 360 cubic inch variant—commonly referred to as the 360 Magnum—was used in a range of Dodge passenger cars, light trucks, and later trucks, often paired with updated cylinder heads and electronic fuel systems. This lineage sits firmly within the small-block camp, even as performance enthusiasts have tuned and swapped components across generations.

How to identify a 360 Magnum and avoid confusion

For practical identification, start with casting numbers and family stamps on the engine block and intake. Mopar’s small-blocks, including Magnum variants, carry different casting codes than the big-block RB/B-family blocks. Visual cues such as valve cover branding and the overall block proportions can also help, but the most reliable method is checking the casting numbers and cross-referencing with official Mopar engine catalogs or reputable databases.

Summary

Bottom line: a 360 Magnum is not a big-block. It is a small-block V8 from Mopar’s Magnum family, designed for lighter installations and a different performance envelope than Mopar’s big-block engines. When planning swaps, restorations, or builds, knowing the engine family matters for fitment, parts compatibility, and reliability. For enthusiasts, understanding this distinction helps avoid costly missteps and guides informed decisions about upgrades and maintenance.

Is the Ford 360 a big block?

Yes, the Ford 360 is a big-block engine, specifically part of the FE (Ford-Edsel) engine family, which is a big-block design. It is built on the same block as the 390 and other larger FE engines, but with a shorter stroke. 
You can watch this video to see the 360 FE Ford Big Block engine: 36sViktor HansenYouTube · Jun 30, 2021

• Engine family: The 360 is part of the FE (Ford-Edsel) engine series, which is considered a big-block family. 
• Shared block: It shares the same bore size with the 390 engine, but the 360 uses a shorter stroke crankshaft, which gives it a smaller displacement (360 cubic inches). 
• Design: Ford created the 360 by "de-stroking" the 390's crankshaft, creating a heavy-duty engine primarily for trucks that favored low-end torque over high-end horsepower. 

This video shows a 1974 Ford F-250 Custom with a 360 Big Block engine: 58sBuilt Tough 1776YouTube · Jul 4, 2021

Is the 5.9 Magnum a big block?

No, the 5.9 Magnum is not a big block; it is a small block V8 engine. It is part of the Mopar small-block engine family, along with its predecessor, the 360 LA, and is a development of the 360-cubic-inch (5.9-liter) engine. 

• Small block: The 5.9 Magnum engine is a member of the Mopar small-block engine family, which includes the 318 and 340 engines. 
• Last of its kind: It was the final version of the classic Mopar small-block engine before the introduction of the modern HEMI engine. 
• Engine family: It evolved from the Chrysler A-series engines and the LA-series engines, which were known for being compact and lightweight. 

How much horsepower does a 360 Magnum have?

The "360 Magnum HP" likely refers to the Dodge 360 cubic inch (5.9L) Magnum V8 engine, which had a factory horsepower rating between 230–260 hp. With aftermarket modifications, this engine can be significantly more powerful, with high-performance crate engines and builds reaching 320 hp and beyond. 
You can watch this video to see a Dodge 360 Magnum engine with stock exhaust manifolds on a dyno: 58sRichard HoldenerYouTube · Aug 5, 2021
Stock 360 Magnum engine 

• Horsepower: 230–260 hp, depending on the vehicle.
• Torque: 300–345 lb-ft.
• Usage: Common in Dodge Ram, Durango, Dakota, and Jeep Grand Cherokee models from 1993–2003. 

Aftermarket and crate engines 

• Crate engines: Available from manufacturers like ATK, offering higher performance than stock. 
• Performance examples:
  • 320 hp: An ATK crate engine with an EFI system, 320 hp, and 410 ft-lbs of torque. 
  • 380 hp: A crate engine with a high-lift camshaft, single-plane intake, and Magnum heads. 
• Custom builds: Can achieve much higher horsepower levels. For example, a custom build with modifications like long tube headers, a Comp Cams upgrade, or a stroker kit can reach over 350 hp and even 500+ hp on a dyno. 

This video demonstrates the power gains from upgrading a Dodge 360 Magnum engine's camshaft: 55sRichard HoldenerYouTube · Aug 19, 2021

Is a Dodge 360 a big block or small block?

The fact is, the small block Mopar LA-engines (318, 340 and 360cid) were under-rated at the factory and were the last of the big three small blocks to be offered to the public.