Those are the old series X12 RB engines, that's why you won't find info on their web site. They've been replaced by the new V12 series. They were equivalent to the old RS12 series of Novarossi engines. What I can't remember specifically is what the 340 engine was. I had a 310 RB and it was a 5 port turbo engine, and I think the 340 was a Rody tuned engine, but i don't know if it was 3 or 5 port turbo or non turbo.
If somebody is offering you one, ask him if it is 3 or 5 port and if it has a black crankcase, if does than it is a Rody tuned version, great engine.........very fast.

AFM