* Mechanical Advance Mechanisms: The internal mechanisms controlling the distributor's advance curve varied significantly over the years. These differences are not easily adjusted or swapped.
* Vacuum Advance Mechanisms: Similar to mechanical advance, the vacuum advance systems changed. Different diaphragms, linkages, and vacuum port configurations exist.
* Shaft Diameter/Length: While often similar, slight variations in the distributor shaft diameter and length can occur.
* Distributor Cap and Rotor: These are usually specific to the distributor and not interchangeable between different years or even different distributors within the same year.
* Electronic vs. Mechanical Ignition: The switch from points-based (mechanical) ignition to electronic ignition (HEI) in the later years introduced major differences. These are not interchangeable.
While some distributors *might* appear to physically fit, attempting to use an incorrect distributor will likely lead to poor performance, misfiring, incorrect timing, or even damage to the engine. Always check the application for a distributor to ensure it's correct for your specific year and engine type. Using a parts catalog or online database specifically referencing your engine's year and details is crucial.
