Can you clarify this? Even at 3 seconds per in game hour that means an in game day takes just over a minute.
If your save game says you're at 500 days, you take that number and multiply it by 24, which gives you in-game hours (12000). Take that number and multiply by 3 and you get the real time seconds you've playing Morrowind (36000). Divide by 60 to get real time minutes (600). Divide by 60 again and you've got real time hours (10). So, for 500 days in days, you've played for 10 hours.
That is, if I've done my math right. That should mean that you can divide your current number of days by 50 to get your total hours. I think.
Of course, that doesn't account for any reloading of previous saves.
edit: Just did the calculations for my own character. I'm on day 230, which would mean I've played for roughly 4.5 to 5 hours. Definitely not right...