Which Engine Uses the 1-8-4-3-6-5-7-2 Firing Order?

The firing order 1-8-4-3-6-5-7-2 is most famously associated with classic American V8 engines, especially the Chevrolet small-block and big-block V8 families, as well as several other traditional cross-plane V8s from U.S. manufacturers. In practice, it identifies a widely used firing pattern rather than a single, unique engine.

Understanding the Question: What Does a 1-8-4-3-6-5-7-2 Firing Order Mean?

When someone asks, “What engine has a 1-8-4-3-6-5-7-2 firing order?”, they are usually trying to match a firing sequence to a specific engine family for tuning, repair, or identification. The sequence 1-8-4-3-6-5-7-2 is a classic firing order for many traditional cross-plane crankshaft V8 engines, most notably older Chevrolet small-block V8s such as the 283, 327, 350, and 400, as well as various Chevrolet big-blocks. However, it’s also used—sometimes with different cylinder numbering conventions—by other domestic V8s.

Engines Commonly Using the 1-8-4-3-6-5-7-2 Firing Order

This firing order appears across several iconic American V8 engine families. Below are the most significant groups of engines that are either directly documented or widely recognized as using 1-8-4-3-6-5-7-2, based on traditional U.S. cylinder-numbering conventions.

• Chevrolet small-block V8 (Gen I classic SBC) – Including the 265, 283, 302, 305 (early carbureted), 307, 327, 350, and 400 cubic-inch engines.
• Chevrolet big-block V8 (Mark IV and related) – Including 366, 396, 402, 427, 454, and some 502 big-block variants.
• Many GM “crate” performance small-blocks – Such as ZZ4, ZZ6, and various performance derivatives that retain the traditional SBC firing order.
• Some marine and industrial V8s based on Chevy blocks – For example, MerCruiser and other marinized V8s built off SBC or BBC architecture.
• Certain older carbureted GM truck V8s – Light- and medium-duty trucks using classic SBC/BBC platforms.

These engines share an underlying cross-plane V8 crank design and a conventional distributor setup, which makes the 1-8-4-3-6-5-7-2 pattern both mechanically convenient and historically entrenched in tuning charts, repair manuals, and under-hood stickers.

The Best-Known Example: Chevrolet Small-Block V8

Among all engines using the 1-8-4-3-6-5-7-2 firing order, the Chevrolet small-block V8 is the most iconic and widely referenced. This is often the engine people mean when they mention this firing order without additional context.

Key Chevrolet Small-Block Engines Using 1-8-4-3-6-5-7-2

The list below highlights popular Chevrolet small-block displacements and applications in which this firing order is standard, especially in pre-LS generations.

• 265 & 283 cu in – Early small-blocks from the late 1950s and early 1960s.
• 302 cu in – High-rev “Z/28” style engines used in first-generation Camaro Trans-Am applications.
• 305 cu in (early) – Widely used in passenger cars and light trucks before widespread adoption of more modern engine families.
• 307 cu in – A transitional small-block used through the late 1960s and early 1970s.
• 327 cu in – Legendary performance and passenger-car engine of the muscle-car era.
• 350 cu in – The best-known SBC variant, used across cars, trucks, and aftermarket crate engines.
• 400 cu in – Large-displacement small-block used in performance and heavy-duty applications.

Across decades, these engines kept the same firing order and a consistent distributor-rotation and wiring convention, making 1-8-4-3-6-5-7-2 almost synonymous with the classic Chevy V8 for many mechanics and enthusiasts.

Why This Firing Order? Mechanical and Design Reasons

The 1-8-4-3-6-5-7-2 firing order is not arbitrary; it arises from balancing vibration, crankshaft loading, intake/exhaust scavenging, and packaging constraints in a cross-plane V8 design.

Cross-Plane V8 Architecture

Most traditional American V8s, including Chevy’s small- and big-blocks, use a cross-plane crankshaft with crank throws at 90-degree intervals. This layout allows excellent primary and secondary balance, contributing to smooth operation at low and medium RPM.

The following points explain why 1-8-4-3-6-5-7-2 fits well with this architecture.

• Even firing spacing – A four-stroke V8 fires one cylinder every 90 degrees of crank rotation; this sequence satisfies that need in a way that spreads pulses across banks.
• Bank-to-bank alternation – The order tends to alternate between left and right cylinder banks when using the GM numbering scheme (driver’s side odd, passenger side even), improving exhaust scavenging and smoothness.
• Crankshaft torsional control – Distributing firing impulses around the crank helps reduce twisting stress and improves durability.
• Compatibility with distributor layout – The order works cleanly with a traditional distributor cap, offering straightforward plug-wire routing.

Taken together, these design advantages explain why this firing order remained standard in Chevy V8s for decades and influenced other engine families with similar physical layouts.

How Cylinder Numbering Affects Perception of Firing Order

Although 1-8-4-3-6-5-7-2 is clear within the GM V8 numbering system, other manufacturers use different cylinder labels and bank conventions, which can make direct comparisons confusing.

GM V8 Numbering vs. Other Systems

The conventions used by different automakers can make seemingly distinct firing orders functionally similar when translated between systems.

• GM typical V8 numbering – Left (driver’s) bank is 1-3-5-7 front to rear; right (passenger) bank is 2-4-6-8 front to rear. Firing order 1-8-4-3-6-5-7-2 is defined in this context.
• Ford V8 numbering (traditional) – On many Ford V8s, one bank is numbered 1-2-3-4 and the other 5-6-7-8, but the firing order might be written as 1-3-7-2-6-5-4-8 or variants, which can be “equivalent” to GM patterns once you map the cylinder positions.
• Chrysler V8 numbering – Chrysler commonly uses 1-3-5-7 on the right bank and 2-4-6-8 on the left, reversed from GM, giving yet another representation of effectively similar phasing.
• Functional equivalence – Two engines can have different published firing orders but very similar physical firing sequences around the crankshaft once their numbering schemes are reconciled.

This is why identifying an engine solely from its firing order can be tricky; the same crankshaft firing pattern may be described differently depending on the manufacturer’s numbering convention.

Modern V8s and Alternatives to 1-8-4-3-6-5-7-2

While 1-8-4-3-6-5-7-2 is historically important, not all modern V8s use it. Changes in emissions, NVH (noise, vibration, harshness), and performance optimization have driven manufacturers toward alternative firing orders.

General Motors LS-Series and Later Engines

GM’s newer V8 families, such as the LS and LT series, generally use a different firing pattern that improves certain performance and refinement metrics.

The list below outlines key differences from traditional small-block firing orders.

• LS1/LS2/LS3/LS6/LS7 typical firing order – Commonly 1-8-7-2-6-5-4-3, not 1-8-4-3-6-5-7-2.
• Improved crank and block loading – The revised order is often chosen to reduce localized stress and improve main-bearing life.
• Refined idle and exhaust tone – Different sequencing changes pressure waves in the exhaust, influencing sound and emissions behavior.
• Aftermarket “4/7 swap” cams – Some builders retrofit older SBCs to use LS-style sequences for similar benefits, changing from the classic 1-8-4-3-6-5-7-2 to a revised pattern.

These developments highlight that while 1-8-4-3-6-5-7-2 is historically standard, it is not universal, even within GM’s own lineup.

Practical Implications: Why Firing Order Matters to Owners and Mechanics

For most drivers, the exact firing order is invisible, but for those working directly on engines, it is foundational information for correct operation.

Key Situations Where Firing Order Is Critical

The scenarios below illustrate where knowing that an engine uses 1-8-4-3-6-5-7-2 is directly useful.

• Distributor and plug-wire installation – When routing spark plug wires on an older carbureted V8 with a distributor, correct sequence is essential to avoid misfire.
• Diagnosing misfires and backfires – Incorrectly wired cylinders, especially after maintenance, often trace back to firing order errors.
• Tuning carburetors and ignition timing – Understanding firing sequence helps interpret plug-readings and exhaust temperature patterns cylinder by cylinder.
• Camshaft swaps – High-performance cams sometimes change firing order; builders must re-wire the engine accordingly.
• Engine swaps and hybrids – Mixing components from different V8 families demands careful cross-checking of firing orders and cylinder numbering.

Because of these factors, repair manuals, under-hood labels, and intake manifolds on older V8s frequently print “FIRING ORDER 1-8-4-3-6-5-7-2” visibly for technicians.

Can Firing Order Alone Positively Identify an Engine?

Although 1-8-4-3-6-5-7-2 strongly suggests a traditional Chevrolet-style cross-plane V8, it is not a perfect fingerprint. Several engine families share this pattern or something functionally similar under different numbering schemes.

How to Narrow It Down

The following additional identifiers are typically needed to confirm the exact engine when you know the firing order.

• Block casting numbers – Stamped or cast numbers on the block and heads can pinpoint the exact engine family and displacement.
• Physical layout – Distributor location (front vs. rear), valve-cover shape, and intake manifold design help differentiate GM from Ford or Chrysler V8s.
• Cylinder numbering reference – Confirming whether the engine uses GM, Ford, or Chrysler numbering avoids misinterpreting a “similar” firing pattern.
• Manufacturer documentation – Factory service manuals or OEM charts list official firing orders and are definitive.

In other words, the 1-8-4-3-6-5-7-2 sequence is a strong clue, but not a conclusive identifier by itself; it must be combined with visual inspection and documentation.

Summary

The firing order 1-8-4-3-6-5-7-2 is most closely associated with classic Chevrolet V8 engines, especially the Gen I small-blocks (283, 327, 350, 400, and others) and many big-block Chevys (396, 427, 454, etc.), as well as a range of related GM-based marine and industrial engines. This order suits cross-plane crank V8 architecture by balancing bank-to-bank firing, improving smoothness, and simplifying distributor wiring.

However, the same or similar crankshaft firing patterns can appear under different numbering schemes in other manufacturers’ V8s, so this sequence alone does not uniquely identify a single engine model. For precise identification, the firing order should be combined with casting numbers, physical layout, and official manufacturer data.

What is the firing order of a LS engine?

The standard firing order for most LS engines is 1-8-7-2-6-5-4-3. This sequence is designed to improve balance and reduce crankshaft stress compared to older V8 designs, resulting in smoother operation. 
This video explains the standard firing order for Chevy engines: 1mBad Influence GarageYouTube · Jan 4, 2021

• Standard LS firing order: 1-8-7-2-6-5-4-3 
• Purpose: This order is specifically designed to alternate between cylinder banks to improve engine balance and reduce torsional vibration in the crankshaft. 

This video explains the 4/7 swap and other firing order changes: 48sDavid FreiburgerYouTube · Jan 22, 2020

What engine firing order is 1-8-4-3-6-5-7-2?

Pontiac (most 1955-81 V8 engines): Counter-clockwise 1-8-4-3-6-5-7-2 (Note: 307 Pontiac V8 engine rotates clockwise)

What does 1-8-4-3-6-5-7-2 mean?

The numbers 1-8-4-3-6-5-7-2 represent the firing order of a V8 engine, indicating the sequence in which the cylinders ignite to create power. This specific order is the most common for many V8 engines, including those from GM, such as small- and big-block Chevys, as well as many Mopar, Buick, and Pontiac engines. 

• What it means: The numbers are a sequence for an 8-cylinder engine. When cylinder #1 completes its compression stroke and is ready to fire, the next cylinder to fire is #8, followed by #4, and so on, until #2 fires last in the sequence. 
• Why it’s important: This order is designed to optimize power, reduce vibrations, and balance the engine. Running with the incorrect firing order can lead to misfires, rough running, and potential engine damage. 
• Companion cylinders: In this sequence, cylinders that fire at the same time (though in different strokes) are called companion cylinders. They are paired as follows: 1 and 6, 8 and 5, 4 and 7, and 3 and 2. 

What is the firing order of a Chrysler V8?

The firing order for most Chrysler V8 engines, including the small block (SBM), big block (BBM), and Hemi, is 1-8-4-3-6-5-7-2. This applies to older engines like the 273, 318, and 340, as well as modern 5.7L and 6.4L Hemi engines and the 4.7L V8. The distributor rotates counter-clockwise on these engines.
 
This video explains the cylinder identification and firing order for a Dodge 318 engine: 39sWirelesSHackYouTube · Aug 28, 2024
Chrysler V8 firing order

• Firing order: 1-8-4-3-6-5-7-2 
• Distributor rotation: Counter-clockwise 
• Cylinder numbering (front to back):
  • Driver’s side: 1, 3, 5, 7 
  • Passenger’s side: 2, 4, 6, 8