The top of a van-type truck owned by Mobil Chemical Corp., Kordite Packaging Di vision, was damaged shortly after 10 p.m. Friday when it struck the GM O underpass in the 500 block of East Super ior. Carl D. Stucker, 21, of Vir ginia, driver of the truck,was headed west when the accident occurred. Damage was confined to the top of the van which was a few inches too tall to clear the rail road bridge. Stucker was taken to Passa vant hospital and examined for a possible neck injury and re leased later.