All the bases I've come across have multi holes to fit various engines.
I wouldn't be surprised if one of the design briefs of the PT was to have the same bolt circle as the American four strokes to save having to make two base moulds.
This could come in handy. I have a very nice Victa alloy base with a shot PT engine (totally seized up, took the parts off it now) and a big, square Quantum 35 I have on a Supaswift alloy base where the wheel stubs have rusted off. I wanted to somehow save the Supaswift base, as I used the engine itself to learn how to fix up a 4 stroke (running very nicely now. Dates from the late 80's/early 90's I think), but I haven't been able to come across the right parts for the base, so I might be able to transplant the Quantum on to the Victa base.
