What is the firing order of a 350 SBC?
The firing order for the 350 cubic inch small-block Chevy is 1-8-4-3-6-5-7-2. This sequence governs which cylinder sparks first and how the ignition system distributes power across the eight cylinders.
What the firing order means for engine maintenance
Understanding the firing order is essential for correctly wiring spark plugs, diagnosing misfires, and timing ignition. For the 350 SBC, the sequence must be followed exactly when installing spark plug wires or adjusting distributor timing to ensure smooth operation and balanced power delivery.
The following list shows the firing sequence from first to last cylinder in the standard Chevy small-block V8 configuration.
- Cylinder 1 fires first
- Cylinder 8 fires second
- Cylinder 4 fires third
- Cylinder 3 fires fourth
- Cylinder 6 fires fifth
- Cylinder 5 fires sixth
- Cylinder 7 fires seventh
- Cylinder 2 fires eighth
In practice, wiring the distributor and spark plugs according to this order helps achieve even firing across both banks of the engine. If the wires are out of sequence, misfires, rough running, or starting difficulties can occur.
Tips for wiring and timing
When servicing a 350 SBC, verify the cylinder numbering used by your specific engine and refer to the factory diagram or service manual. Some aftermarket cams or distributor setups may alter recommended wiring, so always confirm with documentation for your model and year.
Distributor rotation and wiring notes
Most GM small-block distributors rotate clockwise when viewed from above. Use the firing order as your guide when laying out spark plug wires, but if you modify cam timing or install an aftermarket distributor, re-check timing specs and wiring diagrams for the exact configuration.
Summary
The standard firing order for the 350 SBC is 1-8-4-3-6-5-7-2. This sequence underpins ignition timing and engine smoothness across a wide range of years and configurations. Always verify with the exact manufacturer diagram for your engine, especially if aftermarket parts or unusual builds are involved.
What is the SBC firing order?
The standard SBC (Small Block Chevy) firing order is 1-8-4-3-6-5-7-2. This order is crucial for the engine's proper operation and timing. The cylinders are numbered sequentially from front to back, with 1, 3, 5, and 7 on the driver's side, and 2, 4, 6, and 8 on the passenger's side.
This video explains the firing order of the Small Block Chevy V8 engine: 58sfastflo1YouTube · Jan 11, 2021
- Firing Order: 1-8-4-3-6-5-7-2
- Cylinder Numbering:
- Driver's side (left): 1 (front), 3, 5, 7 (back)
- Passenger's side (right): 2 (front), 4, 6, 8 (back)
This video explains the firing order of the SBC 350 engine: 28sDuhe speed shopYouTube · Aug 12, 2023
Which cylinder is number one on a Chevy 350?
On a Chevy 350 V8 engine, the #1 cylinder is the frontmost cylinder on the driver's side. To find it, look at the engine from the front; the bank of cylinders on the left (driver's side) will have odd numbers (1, 3, 5, 7), with #1 being the one closest to the front.
This video explains the cylinder locations and firing order on a Chevy 350 engine: 58sWirelesSHackYouTube · Sep 30, 2024
How to locate cylinder #1
- From the front of the engine: Identify the bank of cylinders on the driver's side (the left side when facing the engine from the front). This is bank #1.
- Find the front cylinder: Within that bank, the cylinder closest to the front of the vehicle is cylinder #1.
- Alternative method: The #1 cylinder is on the side of the engine that is further forward (the side with the belts).
Why knowing cylinder #1 is important
- Spark plug and wire routing: Knowing the #1 cylinder is crucial for correctly connecting the spark plug wires according to the firing order.
- Distributor cap alignment: The #1 terminal on the distributor cap is a reference point for setting ignition timing.
- Engine diagnostics: Correctly identifying the #1 cylinder is essential for troubleshooting and making adjustments to the engine, as misfiring or incorrect timing can be caused by improper spark plug wiring.
You can watch this video to learn how to find the number one cylinder using the timing marks: 42sSam’s TrucksYouTube · May 27, 2021
Where is number 1 on a distributor cap?
The #1 terminal on a distributor cap is not a fixed position; it's the terminal the rotor points to when cylinder #1 is at Top Dead Center (TDC) on its compression stroke. To find #1, you must find cylinder #1 at TDC on the compression stroke, then identify where the rotor is pointing at that exact moment. The spark plug wire for the #1 cylinder is then connected to the distributor cap terminal that the rotor is pointing to.
This video explains how to find the #1 position on a distributor cap: 59sMotor MatchupsYouTube · Jan 12, 2024
How to find the #1 position on a distributor cap
- Find cylinder #1 at TDC on the compression stroke:
- Method 1 (finger): Place your finger over the #1 spark plug hole. Rotate the crankshaft by hand. When you feel pressure on your finger and the piston "blows it off," you are near TDC.
- Method 2 (pushrods): Remove the valve cover. Rotate the crankshaft while holding the valve pushrods for cylinder #1. The pushrods will be free-spinning (both intake and exhaust) when cylinder #1 is at TDC on the compression stroke.
- Identify the rotor's position: With cylinder #1 at TDC, observe which terminal on the distributor cap the rotor is pointing directly at.
- Connect the #1 spark plug wire: Connect the spark plug wire from cylinder #1 to the terminal that the rotor is currently pointing to.
- Wire the rest of the cylinders: Follow the engine's firing order (e.g., 1-3-4-2 for a common four-cylinder) in the correct rotation (usually counter-clockwise) from the #1 terminal to connect the rest of the spark plug wires.
You can watch this video to see how to install a distributor and connect the spark plug wires: 1mPOWERNATIONYouTube · Jul 20, 2024
Important considerations
- The rotor position is adjustable: You can drop the distributor in at any position around the clock, which will change the #1 terminal position. The important thing is that when the rotor is pointing to the #1 terminal, cylinder #1 is at TDC on the compression stroke.
- Adjust for timing: Once set, you may need to adjust the distributor's base position to get the timing just right, especially if there isn't enough room for the vacuum advance canister to operate correctly.
- Look for markings: Some distributor caps have a #1 marking or a notch, but this is not always reliable and can be misleading if the distributor was installed incorrectly.
Is the firing order the same for all 350s?
Since its introduction in 1968, the 350s firing order is 1 8 4 3 6 5 7 2. Just like all other Chevy small and big block engines going back to 1955.
