In my many trips to the wreckers to get parts for my ae82 I have never seen one with a 4a-fc engine. All the CS-X models I have looked at had 4ac engines. They seem easy enough to swap in tho, would only be worth it if u had a dud 4ac. Have a look at this link to a toyota specification pamphlet for the ae82. Does not mention anything about a 16 valve engine apart from the TwinCam 4AGE. The ae92 was the first model to come out with the 4afc in australia.