Use a table ban saw to hack off the 340 piston crown .

Get get yourself a set of triple beams and start weighing em up, if Ya got em! Otherwise contact to manufacturers and if that's not possible because they're a discontinued piston start a separate post on them hopefully someone will reply with the correct information at this point your info is being buried in here
Junkyardhero got me the specs on my pistons, pins, and rings already.