Their was a difference in the heads for the years, same is for the 250 the e 1 has smaller done usally came on a 87 e2 had a larger dome that came on the later years. I have different head for my 250. My 87 had the small dome and my 91 has the larger dome and my 88 has the larger dome. It is the way Suzuki done them.I dont know why they change them.