nope, the engine number won't tell you, or us ?, what you have ?, but the vin number will and does !the engine vin doesn't help?
Are you the one they call Dr Feelgood?300ex first year was 93. Before that was the 250x from 87-92 (not to be confused with the 250x started in 09 but is really the 250ex)
If you post a pic that will help also
Rob
Honestly you could stick more money in performance parts into it than it's worth and you still won't keep up with a stock 400ex, or be as reliable. I would ride it as is till you get bored of it and then upgrade to something better out of the box.
Rob