Good question and thank you for the response. It is probably at least a year old and I am thinking it is the first "revo/ tmaxx" engine by sirio. Not sure though. Also it is orange and not blue as all the other models I have seen on ebay and such are blue. But hopefully someone here has some knowledge of the engine I am prepared to do a full mod plus ceramic. Since I paid nothing for the engine mod cost are second to "is it worth it".......