The Imperials had tough frames, but then add the front sheet metal was all one welded together piece and just the sheet metal makes them pretty tough. They were Demo kings, that was why they outlawed them.

The real story is, with the exception of a very brief early 80s version, the Last Imperials in NASCAR was back in the 50s on the long tracks. Most were too heavy for smaller tracks, and the dirt track bullrings of those early NASCAR days. The thread title is misleading.