Incorrect firing order on a Chevy 350 engine can cause a bumpy and uncomfortable ride. Hence, it helps to know the precise sequence. To this end, the correct firing order on a Chevy 350 is 1-8-4-3-6-5-7-2. This firing order simply means that the number 1 spark plug should be followed by the number 8 spark plug and then the number 4 spark plug in that order in a clockwise direction.
Furthermore, knowing the correct firing sequence balances the engine, allows smooth operation, and reduces vibrations.
In this article, I’ll tackle Chevy 350 (SBC and BBC) firing order to complete the ignition pattern as it should.
Chevy 350 (5.7 Vortec) Firing Order
The Chevrolet small-block V8 has changed the automotive engine industry. This technologically advanced and innovative motor debuted in 1955 as a 256-cubic-inch, 4.3L engine.
In 1967, this engine was developed into a 350-cubic-inch beast and was first used in the Camaro. While it was based on the 327-block, the Chevy 350 came with an all-new crankshaft featuring a 3.48-inch stroke.
Later, this engine was used in most passenger cars, race cars, off-road trucks, motorcycles, and even boats. Chevrolet used it in the Corvette, Caprice, Buick, and Cadillac. Thanks to its quiet operation, reliability, and impressive ability for tuning, this engine was embraced by GM, competitors, and enthusiasts.
By 1985, Corvettes used a fuel-injected version of the Chevy 350 engine. However, other passenger cars with the Chevy 350 still utilized a four-barrel carburetor. Furthermore, Chevrolet employed a computer-controlled emission system on all their Chevy 350 engines, beginning in the 1980s.
To date, the Chevy 350 engine is a 350-cubic-inch small-block V8 with a 5.7L capacity. It also features a 4.00 bore and 3.48-inch stroke. However, depending on a car’s year, make, and model, the horsepower may vary from 145 to 370. In addition, it boasts up to 380 pound-feet of torque which makes it a good choice for towing.
In 1997, the Chevy 350 was superseded by Generation III LS but was discontinued in 2003. Today, it is not offered as a standard motor but as a crate engine for hot rodding purposes.
The firing order of Chevy 350 is 1-8-4-3-6-5-7-2. The Chevy 350 firing order is a pre-determined sequence of when each cylinder gets a spark from the ignition system.
Since the Chevy 350 is a V8 engine, all eight cylinders should not fire at the same time. It needs proper timing and configuration where one cylinder is firing while the others are on a different stroke but working in sync.
A V8 engine needs coordinated firing to ensure smooth operation and minimize vibrations. Additionally, it provides a comfortable ride and thus prevents long-term damage to the engine.
Read more: SBC Head Casting Numbers: Full List Lookup
HEI Distributor Chevy 350 Firing Order
A High Energy Ignition (HEI) distributor cap usually has its firing order, but it’s not necessarily different from the engine’s firing order. An HEI distributor cap is a small device that facilitates the transfer of electric energy from the ignition coil to the spark plug.
SBC V8 engines utilize an HEI distributor cap whose firing order follows a clockwise direction. However, the number one position on your HEI distributor cap does not matter as long as you have the spark plugs in the correct firing order.
Equally important is that the firing order should follow the same pattern as the engine. In other words, HEI distributor Chevy 350 firing order is 1-8-4-3-6-5-7-2. This firing order is identical to Chevy point distributor.
Small Block Chevy Firing Order
Small-block Chevy (SBC) engines are known as “small-block” because they are significantly smaller than their big-block Chevy (BBC) counterparts. They feature 262 to 400 cu in, compared to 348 to 572 cu in displacement on the BBC.
Chevy 350 firing order is the same across all its small-block V8 engines, which means that the SBC firing order is 1-8-4-3-6-5-7-2. The small-block motor includes the 262, 265, 267, 283, 302, 327, 350, and 400. The SBC firing order means that cylinder number 1 fires first, followed by cylinder number 8, cylinder number 4, and so on.
To know which cylinder is number one, you’ll have to look from the front of the engine on the driver’s side to the rear. Hence, the front-left cylinder is number 1. All alternating numbers start from the left, going to the right. Equally important, all cylinders with even numbers will be on the engine’s right side.
Fundamentally, the odd-numbered cylinders are located on the driver’s side, while the even-numbered cylinders are on the passenger’s side.
The 1-8-4-3-6-5-7-2 firing order applies to all small block Chevy engines, such as:
- 262 Chevy
- 267 Chevy
- 265 Chevy
- 283 Chevy
- 302 Chevy
- 305 Chevy
- 307 Chevy
- 327 Chevy
- 350 Chevy (5.7 vortec)
- 400 Chevy
This order excludes LS1 to LS7 engines that do not run at the same SBC firing order. Instead, LS1 through LS7 run at 1-8-7-2-6-5-4-3. This firing order is similar to the 5.3L engine, different from other Chevy vehicles with a small-block Chevy motor.
Read more: Chevy 350 vs. 305: Which Is the Better Engine For You?
Big Block Chevy Firing Order
Big-block Chevy (BBC) V8 engines have a similar firing order to SBC V8 engines; 1-8-4-3-6-5-7-2. It applies to all BBC engines such as:
- 366 Chevy
- 396 Chevy
- 402 Chevy
- 427 Chevy
- 454 Chevy
- 502 Chevy
- etc.
BBC firing order also means that when the piston is at TDC (Top Dead Center), on the compression stroke, you should align the rotor inside the distributor with the number 1 spark plug terminal in the distributor cap.
Additionally, this firing order works on other V8 engines from other manufacturers, including GM, Chrysler, and Ford Windsor (excluding 351). Even then, it may seem like GM’s firing order is different because of how its cylinders are numbered, but the sequence remains similar to Chevy 350.
Chevy 350, SBC, and BBC Firing Order Diagram
Chevy Small Block and Big Block Cylinder Numbers
Conclusion
The Chevy 350 firing order is similar for SBC and BBC V8 engines. Fortunately, the cylinders are arranged in a manner that makes it easy for Chevy fans to figure out the firing order quickly.
Still, it’s essential to label the distributor cap, and the spark plug ends with their corresponding cylinder number. This way, you will put back the spark plugs in the correct order when it’s time to crank the engine over.
I hope you now know the firing order of the Chevy 350 engine by heart before you embark on a new project.
Read more:
