I had a look at some Victa models on display at Bunnings in Hillsdale, Sydney that could be fitted with a Powertorque down the line. As we know, there are a lot of good Powertorques that outlast their bases and a lot of Briggs that give up the ghost before the bases fail. I have highlighted the extra mounting hole evident on these mower's bases that are used only by Powertorque motors. There is even a combo blower and mower pack with a "classic cut" Victa on the box.
Ahh, if only victa had kept producing the thumblatch catcher series, they would be in better shape today!