In order to extract the full measure of performance and economy from your engine it is essential that it is properly tuned at regular intervals. A regular tune-up will keep your car's engine running smoothly and will prevent the annoying breakdowns and poor performance associated with an untuned engine.
All 1964-74 models use a conventional breaker point ignition system. In 1975, Chevrolet switched to a full electronic ignition system known as HEI.
A complete tune-up should be performed at least every 15,000 miles (12,000 miles for early models) or twelve months, whichever comes first.
Because of improved materials and engineering, 1981 and later models have an increased tune-up interval of 30,000 miles.
This appropriate interval should be halved if the car is operated under severe conditions such as trailer towing, prolonged idling, start-and-stop driving, or if a driveability problem such as hard starting or poor running is noticed. It is assumed that the routine maintenance described in Routine Maintenance has been kept up, as this will have a decided effect on the results of a tune-up. All of the applicable steps of a tune-up should be followed in order, as the result is a cumulative one. Any adjustment made to the engine is normally performed only when it will not be affected by other adjustments that are yet to be made during the tune-up.
If the specifications on the underhood tune-up sticker in the engine compartment of your car disagree with the Tune-Up Specifications chart in this Section, the figures on the sticker must be used. The sticker often reflects changes made during the production run or revised information that apply to the particular systems in that vehicle.