However, generally speaking, for both engines in a 1994 Aerostar, conventional motor oil meeting the API classification SG, SH, or SJ would have been appropriate at the time. Modern oils meeting SN or even SP are also likely compatible and often preferred for better performance and protection. The viscosity will also depend on your climate. Consult your owner's manual for the recommended viscosity grade (e.g., 5W-30, 10W-30). Using the wrong viscosity can harm your engine.
It's crucial to consult your owner's manual for the exact specifications. The manual will provide the correct oil type and viscosity for your specific Aerostar model and engine. You can often find a digital version of the manual online through a Ford parts website or a general automotive manual provider.
