The 450 & Maia.
In 1961, three years after the introduction of the subaru sedan, Fuji Heavy Industries decided they needed something with more power, and they had the export market on mind.  The "450" engine was their answer.  Actually only 423cc but was good enough for 22hp as compared to the 356cc engines 16hp.  The engine was put into a deluxe like version of the sedan and also into the new Sambar line.   The 450 sedans differ from the 360 sedans in having higher mounted bumpers with over riders and a better interior. 
In some export markets such as australia the 450 was known as the maia.  The maia was also available as a convertible.  In 1964 production of the convertible models ceased.  Then in 1966 the entire 450 line was ended.  Subaru had a "real" big car now, the 1000.  And the 356cc engine was now capable of 20hp.
left: Here's the convertible version.  Drivers of American versions of the 360 take note of the old style hood with horizontal slats, and the fuel tank cap/measuring cup for mixing the oil.  Those bumpers look pretty cool too, eh?
SEDAN SAMBAR BACK
Above: to the left a picture showing the cimbing power that 22hp could provide, 4 people going uphill.  Maybe they rolled it backwards for the picture?  To the right, the oldest subaru in Australia, a 1961 maia. click on picture for a link to the restorers website.
Click here for a Maia Brochure!