I have an 85 Honda 1.5 Civic DX, it is a carb car. The head is cracked. The casting is PEO-3 and I can't seem to locate one. Is there an interchange or another choice? Any help appreciated.

 

It's an E series, which hasn't been made since 87. That's going to be hard to find. I'm not sure if all E-series are interchangeable.
Although, you could do an engine swap. You can find an older D-series engine for a few hundred bucks.