I've seen y-block's tripped over the mother's used them as anchor's etc. can't recall what the pistons were exactly, but seem to recall both countries using cast and steel. depended on where you lived and how cold it got.
thats why the flat head V8 never survived in australia.
The engine was designed for the states, trouble was it was sold where it was alway's cold (frozen actually) the exhaust ports ran through the head, so the head warmed up quickly and so did the motor. then bang gaskets used to blow etc, including the odd engine. In Australia it was different it used to heat up and overheat. you can't win.
then they solved that problem, there was an overhead conversion kit designed by 2 german's, zardon and dunkoff. this eliminated the flat head design and solved some of the problem until the first original overhead motor was designed in 1954. hence the y-block or 272.