Complex sentence: Billy's next run is the one a lot of people identify him with the WWF National expansion where he did job's from April until December 1984 the one exception was a match against the Iron Sheik where he was allowed to shine even though he lost.
Split into simpler sentences: Billy's next run was with the WWF National expansion where he did jobs from April until December 1984. He also had a match against the Iron Sheik during this time where he was allowed to shine even though he lost.