This means that the spark plugs fire in that order, starting with cylinder #1 and moving around the engine in the order listed.
Important Note: There are two different versions of the 351 Ford V8:
* 351 Windsor: This is the more common version. It has a firing order of 1-5-4-2-6-3-7-8.
* 351 Cleveland: This version has a different firing order of 1-8-4-3-6-5-7-2.
Make sure you know which version of the 351 you have before using the firing order.
