On his year, 1985, it should be the "boost-cocked" style of AFRC, so if the diaphragm is torn/ripped, then it will have lots of black smoke, during acceleration; and will NOT limit hp at all(it NEVER gets "cocked" to limit fuel/rack travel)

Around 1991, the serial number prefix "3ZJ" engines, had "oil-cocked" AFRC, then with oil pressure , they limit fuel until boost pushes on the diaphragm(assuming a good diaphragm), but if the diaphragm is blown/torn/ripped, then it DOES limit hp severely(if adjusted correctly, and not super "rich" AFRC setting)

Now, the newer "oil-cocked" AFRC do fit older engines/governors, so anything is possible, depending on what is on his engine.