I know that there are already two mods out there for a Detroit Diesel series 60 engine sound mod, but both of them aren't very good. I found a good, clear recording of the engine sound on youtube, it would be cool to se something done with it.
http://www.youtube.com/watch?v=nbMfyNCW_gg
http://www.youtube.com/watch?v=nbMfyNCW_gg