Thanks for that Ian.
I wish I had that book but it is out of print.
Note in the top photo that the engine has a flo-jet carby; the one in the
bottom picture has a pulsa-jet like the Vi-Cut.

To continue the question I set above:
does the Briggs engine match other features on the mower? The answer must be No!

Turner rightfully (in my view) claims to have introduced the 4-stroke to
Australian rotaries in late 1959. During 1960 everyone wanted to jump on
the 4-stroke bandwagon. Kirby�s locally made Tecumseh engines would
dominate the 1960s, but Villiers Lightweigh 4-strokes would also appear.

Briggs at this time was the underdog, but found a loyal friend in
Queensland�s Rover. The earliest advertising I have for a Briggs on an
AUS rotary dates from late 1960. HG Palmer�s Standard and Deluxe Utility
mowers offered them. Here are two ads from 1961 and 1963. Note the 8 Series
in the second ad has the Vacu-jet carby.

[Linked Image]
[Linked Image]

The 8 Series offered four types of starting: rope, rewind, wind-up and even
electric. In Australia, I have only found the wind-up starter on early 1960s
engines.

[Linked Image]

The Briggs engine on the Vi-Cat belongs to the early to mid 1960s. It cannot
belong to the 1950s if fitted to an Australian lawnmower. The muffler is home-made
and there is clear evidence that it was a wind-up version.

So, is the chassis from the 1950s or 1960s? To be continued ...