Only oils which are high detergent and are graded MS or SE should be used in the engine. Oils should be selected for the SAE viscosity which will perform satisfactorily in the temperature expected before the next oil change.
Factory recommendations for fuel are regular gasoline with an octane rating of 91 RON or higher for Types 1, 2, 3, 1972-73 Type 4 and 1974 Type 4 equipped with automatic transmission. The 1971 Type 4 and 1974 Type 4 equipped with manual transmission require premium gasoline with an octane rating of 98 RON or better.
All 1975 and later models sold in California and all 1977 and later models sold in the other 49 states use catalytic converters to lower exhaust emissions, requiring the use of only lead-free regular (91 RON) fuel. Failure to do so will render the converter ineffective.
If the vehicle is used for towing, it may be necessary to buy a higher grade of gasoline. The extra load caused by the trailer may be sufficient to cause elevated engine knock or ping. This condition, when allowed to continue over a period of time, will cause extreme damage to the engine. Furthermore, ping or knock has several causes besides low octane. An engine in need of a tune-up will ping. If there is an excessive carbon build-up and lead deposits in the combustion chamber, ping will also result.