You can go to the FAA site
http://registry.faa.gov/aircraftinqu...ef_inquiry.asp
type in Cessna and 337, then t337, then p337 and you will get all the 337's in US registry. You may have to punch in M337 for the o2's. It take a little playing with to figure it out but it works real good.
Have fun.
Ed Coffman
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