Do you have a diagram of firing order for a 73 Pontiac catalina?

Yes, the firing order for a 1973 Pontiac Catalina, which typically features a V8 engine, is 1-8-4-3-6-5-7-2. The cylinder numbering starts from the front of the engine on the driver's side, with cylinder 1 being the first on that side. The cylinders on the passenger side are numbered 2-8, moving from front to back. For a visual diagram, you may want to consult a repair manual or online resources specific to Pontiac engines.