* Firing order: This is the sequence in which the cylinders fire. You'll need a specific workshop manual for the exact firing order.
* Cylinder location: This refers to the physical placement of the cylinders in the engine block (e.g., 1-2-3-4-5-6-7-8 from front to back on one side of the V). Again, a workshop manual will provide a diagram.
* Numbering on the engine itself: The numbers might be cast into the engine block itself, but their location varies by engine and year.
To get the precise information you need, you should consult a 1990 Cadillac Seville repair manual specific to the engine it had. You can find these manuals online (e.g., eBay, Amazon) or at auto parts stores.
