I picture or some more information might help. Sometimes digits can be mis-read (S vs 5, 8 vs B, etc.) and/or faded.
Other information can also be of value narrowing things down, like what eqiupment it is in (or came out of), any date code or other information on the IC. The size and type (DIP, QFP, etc., number of pins).
If it came up with a simple google search, I'm sure you wouldn't already done that. This may take a little more effort.