imported post
good advice from Eamonn. The head studs often break, but its the thin threaded part that shears off and the fat stud still sticks out about 12mm (plenty to get a vice grips onto). Clever of Honda to design the studs this way as it saves a lot of grief. You will very likely break a few of them so just buy a full set and keep the unused ones for future reference.
otherwise it's a straight swap between the 87 & 84.