You MUST determine which engine is in your truck before proceeding. Check your vehicle's documentation or the engine block itself for the displacement (4.3L or 5.7L).
If it's the 4.3L Vortec V6:
* Firing Order: 1-3-5-2-4-6
* Plug Gap: 0.045 - 0.050 inches (consult your owner's manual for the precise specification)
If it's the 5.7L Vortec V8:
* Firing Order: 1-8-7-2-6-5-4-3
* Plug Gap: 0.040 - 0.050 inches (consult your owner's manual for the precise specification)
Crucially: Always consult your owner's manual for the most accurate and up-to-date information on spark plug gap specifications for your specific vehicle and engine. The ranges given above are general guidelines, and the exact recommended gap might vary slightly. Using the wrong gap can negatively impact performance and engine longevity.
