This is a standard firing order for most small-block Chevrolet V8 engines, including the 305 and 350.
Here's a quick explanation:
* 1, 8, 4, 3 are the cylinders on the passenger side of the engine (right side when facing the engine).
* 6, 5, 7, 2 are the cylinders on the driver side of the engine (left side when facing the engine).
This firing order ensures smooth and balanced combustion, resulting in better performance and less vibration.