I appreciate all the suggestions, but I may have gotten in over my head here. I didn't even know what an AIFF file was until I got Wiretap. I am not techo proficient at all. So maybe I haven't been clear about my level of ability(technologically speaking) or my intent: I am tech non-sophisticated; I want to keep the file uncompressed; I want to chop off about two and a half hours from the end; and, if possible, I want to slice out a few pieces in between.
Like I said, I may be in over my head here. Maybe I need to learn a few things before I can do this. Fortunately, I've got lots of room left on my HD so I can leave the file there until I learn how to do this, or until I lose interest and just toss the file.