An Alexander County firefighter died yesterday afternoon in a crash near Taylorsville.  The State Patrol indentified William Shook as the man whyo died in the head-on crash five miles west of Taylorsville on highway 90. The wreck occurred when Shook crossed the centerline and into the path of a dump truck, according to the SHP report.   He was 42 and was a lieutenant at  the Taylorsville Fire Department.   Officials said he died at the scene.