I ran a Toro Groundmaster 72" back in the early 1980's for a summer while between real jobs. Does anyone know what years these were made and when they were discontinued? They were a great machine for level ground, but really stunk on hills, terraces, swales, etc. I don't see them on Toro's web site any more, so I guess the ZTR mowers took their place. Anyone else have experience with one of these?