However, a good starting point and generally accepted range is 0.035" to 0.045".
To find the precise specification:
1. Check your owner's manual: This is the best source for the manufacturer's recommended gap.
2. Consult a Chevrolet parts catalog for your specific year and engine: This will provide details for the original specifications.
3. Look at the spark plugs themselves: Sometimes, the recommended gap is printed on the spark plug.
4. Check your ignition system: The type of ignition system (points, electronic, HEI etc.) can influence the ideal gap. Consult a repair manual specific to your engine and ignition system.
Without knowing the exact details of your Chevelle's ignition system, 0.040" is a reasonable compromise to start with. However, always double-check your owner's manual or a reputable service manual for the most accurate information.
