What heads are on a 1987 Chevy 305?

The 1987 Chevy 305 small-block V8 typically used vortec heads. However, it's crucial to understand that "vortec" is a *later* designation for a specific type of head. 1987 305s did *not* have the Vortec heads as we know them today. They used earlier designs, often referred to as "small-port" or "centerbolt" heads. The exact casting number will determine the specific head design. To know for sure, you need to look at the casting number on the head itself.