To visualize it: Imagine the engine as two banks of four cylinders each, forming a "V". Cylinders are numbered sequentially, typically starting from one bank and going to the other. The exact cylinder numbering sequence might vary slightly depending on the specific engine orientation and how Ford designated it in their documentation, but the basic principle remains. You'd have cylinders 1-4 on one bank of the V and 5-8 on the other. Consult a specific engine diagram for your truck's year and model for the precise numbering and location.
