hi there,
the choke set up on the 16 and 18 are different as well, it's a bit fiddly but you need too change the rod and linkages over, not a big job but make sure you've got some long nose pliers and a good screwdriver.also the two throttle cable end's are different as well if i remember rightly i ended up cutting a washer to fit them over the brackets if not both then certainly one of them(think the top one).the air solenoids just unscrew,and stephenrc45 was right about everything he said.hope it helps
mik.