It is 11 cubic inch, where the usual size for mower engines at that time was 9 cubic inch, so it would have been 3.5 to 4 hp. It had the automatic choke version of the PulsaJet, and the normal (for March 1982) vertical pull starter. I can't tell whether it had points or Magnetron ignition - that was just about the time Briggs changed over.
Those little brackets seem to be injection moulded zinc, so they were made by a serious manufacturer, they aren't "the tenant's improvements", but they are horribly ugly and the installation is very crude. I don't believe Briggs would ever have screwed such a crappy bracket on with self-tappers right across the identification number. They wouldn't have been pleased with Masport doing it either, but I don't suppose they could have stopped them from doing it. Alternatively they may have been parts of some aftermarket kit - perhaps they were part of a device that would make it manufacture its own fuel from water and dog turds, while increasing its power by 600 percent.
