Do you enjoy maintaining your Chevy 350? If you do your own maintenance and repairs, it’s important to know the Chevy 350 firing order. The firing order of a Chevy 350 engine is that important, as it can determine whether the vehicle will run, or won’t run; you don’t want to get it wrong!
I’ve included the Chevy 350 firing order and an overview of the basic Chevy 350 engine in this article. I discuss why firing order is important, and I also take a moment to address some of the differences between other engine firing orders. At the end of the guide, I answer some of your frequently asked questions about various Chevy firing orders.
What Is the Firing Order of a Chevy 350?
The Chevrolet 350 engine has a firing order of 1-8-4-3-6-5-7-2. Most all of the old-school Chevy engines used this firing order.
This firing order shows the firing order sequence of the spark plugs and wires for the spark plugs to fire correctly if the engine uses a distributor. In order for the spark plugs to fire correctly, the Chevy 350 must be wired this way to follow the correct firing order.
Required to set up the firing order, is knowing where the piston hits top dead center on the compression stroke. The rotor in the distributor is meant to align into the correct spark plug terminal in order for the firing order to work correctly. The Chevy 350 engine, starts with the #1 spark plug, which would be the first plug in the distributor cap.
Some small block engines utilize the High Energy Ignition (HEI) distributor. In this case, the electric energy travels from the ignition coil directly to the spark plug and moves in a clockwise motion.
Another example of the common firing order with the Chevy 350. LS engines can also be a 350 and use a firing order of 1-8-7-2-6-5-4-3. If you are not sure how your Chevy engine is wired, in all honesty, it is always best to reference the information in your service manual. Even if you think you are sure to make sure does not hurt.
What is a Chevy 350 Engine?
Chevy 350 engines measure 350 cubic inches or 5.7 liters. All of the 350 engines are small block V8’s that have a 4.00″ bore and 3.48″ stroke. Horsepower varies from 145 to over 370, depending on make, model, and year.
It is also capable of delivering up to 380 lb-ft of torque. When it comes to towing, the 350 is one of the best. Fuel mileage will never be a strong point of the V8 engine.
The 350 small block engine was first introduced in the 1967 Camaro in the form of the L-48 high performance engine. The next year the engine was used in the Chevrolet Nova. By 1969, the entire Chevy lineup incorporated a 350 small block.
GM commonly uses RPO (Regular Production Option) codes to identify the engines, and you will find a 350 code stamped on the cylinder head (most likely on the passenger side of the vehicle). Most likely, the alternator will be in the way, at least you would have more information about your vehicle’s engine.
Most engine codes begin with an L, i.e. L31, L46, etc. However, there is also other codes such as ZQ3 too.
What is an Chevy 350 Firing Order?
A firing order is the order in which the spark plugs fire. An engine cannot operate properly without a firing order. As long as the firing order is right, the engine will run like it was designed. If the firing order is not right, then the ride can be uneven or worse, the engine will not run.
Using the firing order of 1-8-4-3-6-5-7-2, it is easy to see that #1 is the first plug to fire. It is then #8, #4, #3, #6, #5, #7 and #2 follows in its own order. The ignition order is how the spark is created where it needs to be.
When the combustion pressure pushes the pistons down, the transmission gears will move along with the crankshaft. It is the movement that creates the forward or backward motion to go anywhere.
What Makes the Firing Order Important?
Most people think it is irrelevant in what order the spark plugs are fired, but it is not the case! Each cylinder sequence is important for the motors fuel economy and performance. It can also have an impact on the engine’s emissions.
If the cylinders do not fire in the right order, the engine will have fuel that is not burned exiting out of the engine. Depending on how serious this condition is, an improper air and fuel ratio will lead to a no start situation. At the very least, you could see serious performance issues.
Small Vs. Big Block Chevy Firing Order
For small and big block Chevy engines, there are almost completely the same firing order. And the most common firing order is 1-8-4-3-6-5-7-2.
Here are the small block engines that follow this firing order:
- 265
- 283
- 302
- 327
- 350
- 400
With big block engines you can find the firing order also:
- 396
- 406
- 427
- 454
With both of these engines, you get a powerful V8. In fact, all these motors were designed to deliver lots of power for a fun ride.
The newer small block engines are different. They are called LS engines, and when you use a 350 the firing order is changed to 1-8-7-2-6-5-4-3.
So what is specifically the difference between the small block and big block Chevy? Size is the main differentiator. Big block Chevy motors are in fact bigger than small blocks. It’ll probably weigh more too but the big block will create more power.
Other Chevy Firing Orders
1. 327
The Chevy 327 motor was in cars from 1962 to 1969. For the last year it was the standard V8 for all full-size models and was cheaper than the 307 V8 (found in the Camaro, Nova and Chevelle).
The 327 small block Chevy motor has the same firing order, or sequence, as the 350. If you’re wondering the firing order, use this one: 1-8-4-3-6-5-7-2.
2. 454
In 1970, the 454 was a 7.4-liter. The 454 was first introduced in the Corvette’s LS-5 and produced 390 HP. The 454 was later offered with 465 HP.
The 454 big block Chevy motor has the same firing order as the small block 350. Set it for 1-8-4-3-6-5-7-2.
3. 5.3-Liter
The 5.3-liter Chevy motor is a newer design. This means it has a different firing order than the 350.
In the 5.3 liter 350 motors, the firing order is 1-8-7-2-6-5-4-3. Odd cylinders are on the driver’s side of the car. Even cylinders are on the passenger’s side of the car.
4. With HEI Distributor Cap
The HEI (High Energy Ignition) distributor cap is a newer style. In this case, the distributor means that the distributor cap sends voltage from the ignition coil to the spark plug.
After all is said and done, the firing order remains the same as the 350 small block. It is still 1-8-4-3-6-5-7-2.
What If the Firing Order of a Chevy 350 is Wrong?
If you mess up the routing of the plugs on an older motor with a distributor, it can misfire, run poorly, or not start at all.
If you have just replaced plugs or wires and it is not running correctly, the firing order could have been misconfigured. This can easily be avoided by changing only one plug and wire at a time.
How Do I Fix the Wrong Chevy 350 Firing Order?
If you misconfigured the firing order of the Chevy 350 motor, you will need to fix it if you are going to drive the car and get it to run normally. Rotate the crankshaft by hand until you see the timing mark align with the Top Dead Center (TDC) marker on the time cover.
Remove the distributor cap and note where the rotor is pointing. It must be pointing at the number one terminal on the cap.
If not, then rotate the crankshaft again until the rotor is pointing to the number one position on the cap. Follow each wire to ensure it connects to the correct spark plug.
Where is the Number 1 on a Chevy 350 Distributor Cap?
The cylinder numbers start at the front of the engine, beginning on the driver’s side, for your Chevrolet 350 motor with the second cylinder on the front of the passenger’s side.
These cylinder numbers run from left to right and switch sides. If you are having an issue with locating these, you can look at a Chevy 350 firing order diagram.
Where can I find a Chevy 350 firing order diagram?
I’m going to provide a firing order diagram for your Chevy 350, but you can also find other resources with the cleared firing order. Look in your Chevy service/repair manual, or just perform a search online to locate the correct firing order.
The good thing about newer cars with coil over plug design is you no longer have to remember firing orders.
But if you love your Chevy 350 and you love to fix it, the firing order is certainly going to save you a bunch of headaches. The firing order for your Chevy 350 is mostly 1-8-4-3-6-5-7-2 but there are some variances.
That being said, it is best to check the reference information inside your Chevy service manual because the discrepancies with the firing order could create a huge headache.
Why do that and check your engine isn’t going to run right by connecting the distributor with the incorrect Chevy 350 firing order. If you require additional help just contact your local auto repair shop to assist.