This is a generalized drive belt diagram of a 1970 Mustang 302-2V or 351-2V showing how the belts should be installed. The options shown are
1. With A/C and P/S,
2. With P/S but no A/C, and
3. No A/C or P/S.
In this schematic, the drive belts have been color-coded to help visualize the order in which the belts install. The pulleys are footnoted with the casting number that is stamped into them to identify which pulley is used for the correct application. This information is from reputable sources including the Ford master parts catalog. Over the years many parts get changed or removed, often involving incorrect parts. Hopefully this will help to clarify what pulley and belt arrangement is best suited for your application.