What is the firing order on a 5.7 350 Vortec?
The firing order is 1-8-4-3-6-5-7-2. This sequence is used by GM for most small-block Chevy V8s and dictates which cylinder fires first and in which order, regardless of ignition system.
Firing order in practice
To understand how this sequence plays out on a 5.7L Vortec 350, here is the official firing order as it occurs in the engine cycle.
- First: Cylinder 1
- Second: Cylinder 8
- Third: Cylinder 4
- Fourth: Cylinder 3
- Fifth: Cylinder 6
- Sixth: Cylinder 5
- Seventh: Cylinder 7
- Eighth: Cylinder 2
Understanding this sequence is essential for correct spark plug wiring, distributor cap rotor orientation (in distributor-equipped engines), and diagnosing misfires or timing issues. It also helps when replacing ignition components and verifying that the ignition system is firing in the proper order.
Cylinder numbering and layout on a 5.7L Vortec 350
GM’s small-block V8 uses a two-bank arrangement. For reference, cylinder numbering is typically as follows: the front of the engine is toward the timing cover, the left bank (driver’s side) runs cylinders 1, 3, 5, 7 from front to rear, and the right bank (passenger side) runs cylinders 2, 4, 6, 8 from front to rear. This layout helps you map the firing order to the physical locations on the engine.
- Front of engine, driver’s side: Cylinder 1
- Front of engine, passenger’s side: Cylinder 2
- Next rearward on driver’s side: Cylinder 3
- Next rearward on passenger’s side: Cylinder 4
- Next rearward on driver’s side: Cylinder 5
- Next rearward on passenger’s side: Cylinder 6
- Rear-most on driver’s side: Cylinder 7
- Rear-most on passenger’s side: Cylinder 8
Note: Whether your 5.7L Vortec uses a traditional distributor or a coil-on-plug setup, the underlying firing order remains the same. Wiring paths or coil activation will be arranged to deliver spark to cylinders 1, 8, 4, 3, 6, 5, 7, and 2 in that order.
Summary
For a 5.7L Vortec 350, the standard firing order is 1-8-4-3-6-5-7-2. This sequence governs ignition timing, affects how you wire plugs and caps, and aids in diagnosing misfires. Knowing the cylinder layout helps you translate the sequence into real-world engine work, whether you’re chasing a timing issue, performing a tune-up, or replacing ignition components.
