What is the firing order on an old Chevy?
For most older Chevrolets, the firing order depends on the engine family. The two most common sequences are 1-8-4-3-6-5-7-2 for small-block V8s and 1-8-7-2-6-5-4-3 for big-block V8s. These orders determine the spark plug firing sequence to balance the engine and reduce vibrations.
Firing order for the small-block Chevy
This list covers the standard firing order used by the most common small-block V8s found in Chevrolets from the 1950s through the 1980s, including 265, 283, 327, and 350 engines. The sequence is the order in which cylinders fire, which guides the wiring and distributor timing for proper operation.
- First cylinder to fire: 1
- Second cylinder to fire: 8
- Third cylinder to fire: 4
- Fourth cylinder to fire: 3
- Fifth cylinder to fire: 6
- Sixth cylinder to fire: 5
- Seventh cylinder to fire: 7
- Eighth cylinder to fire: 2
This firing order applies to the majority of factory-installed small-block Chevys, but there can be year- or model-specific variations. Always verify against the exact engine build sheet or factory service manual for your vehicle.
Firing order for the big-block Chevy
Older big-block Chevys (such as the 396, 427, and 454 families) use a different standard firing order from the small-blocks. The sequence below reflects the common factory firing order used on many traditional big-blocks.
- First cylinder to fire: 1
- Second cylinder to fire: 8
- Third cylinder to fire: 7
- Fourth cylinder to fire: 2
- Fifth cylinder to fire: 6
- Sixth cylinder to fire: 5
- Seventh cylinder to fire: 4
- Eighth cylinder to fire: 3
As with the small-blocks, variations can exist depending on the exact big-block design and production year. Confirm with the appropriate service manuals or manufacturer specifications for your particular engine.
Notes on verification and practice
How to confirm the firing order on your engine
When restoring or tuning an older Chevy, use these steps to verify the correct sequence:
- Check the distributor cap and spark plug wires to match the factory firing order for your engine model and year.
- Consult the vehicle’s factory service manual or a reputable restoration guide for your exact engine code.
- If possible, reference the build sheet or VIN-specific documentation to confirm any year-specific deviations.
Common pitfalls to avoid
A incorrect firing order can cause poor starting, misfires, rough running, or vibration. Always ensure the correct order is used for the engine family (small-block vs big-block) and double-check connections before starting the engine.
Summary
For classic Chevrolets, the standard firing orders are 1-8-4-3-6-5-7-2 for most small-block V8s and 1-8-7-2-6-5-4-3 for most big-block V8s. While these orders cover the majority of engines from the mid-20th century, always verify against the specific engine’s service manual or build sheet to account for year- or model-specific variations. Correct firing order is essential for smooth operation, longevity, and proper engine balance.
What is the firing order of a 1985 small block Chevy?
All first- and second-generation Chevrolet small-block V8 engines share the same firing order of 1-8-4-3-6-5-7-2.
What firing order is 1 8 4 3 6 5 7 2?
GM V8 Firing Order
The LS engines number the same but changed the firing order. Because of the popularity and longevity of Chevrolet V8 engines, the 1-8-4-3-6-5-7-2 firing order is the one almost every gearhead learns first. These engines came with distributors that spin clockwise, so that's also a useful reference.
What is the SBC firing order?
Number one is the furthest forward cylinder. And then you have an odd side and an even side so it's 1 2 3 4 5 6 7 8 this engine is a small block Chevy. So we know the firing order is 18436572.
What is the firing order of the old Chevy 350?
Since its introduction in 1968, the 350s firing order is 1 8 4 3 6 5 7 2.
