I have to replace my engine. It seems there are no 4.2's in the area. One salvage yard said people or using the 3.8 L from the mustang. Is this a compatable swap?

 

I don't know about the compatibility issues but, I bought an engine from LKQ salvage and am very happy with it. fair price, good engine and a year warrantee on the engine. I know they will ship and they have locations all over. There might be one near you, do an online search.