Hello all,
The white ones are definitely Mustang GTS's. The Vortex model were either grey/red, grey/yellow and possibly one more color but cant remember. The Vortex was designed in conjunction with the CSIRO and was dropped when the Mustang GTS was birthed. Those models ran from about 85-89 The only real difference between them and the standard alloy bodied 2 strokes was the distinctive Vortex styled blade carrier. They probably dropped the vortex name because royalties may have been paid to the CSIRO for their involvement in the design.
Interestingly enough though the Vortex name was re-birthed in the 90's on a steel based commando styled mower with the only difference being the Vortex blade disk. They carried that model from the early 90's to about 2000. All the vortex models had the poppet valve in the carby facing the letter "A" instead of the usual "C" and was due to the heavier blade carrier and hence the lower RPM that is specified.
