THink the first time i did an fbody window motor it took me 4 hours..
Next time... 2 hours
Then an 1.5 hours..
Now they are down to about 45 minutes for Camaros and about 1 hour for Trans Ams...
Subtract about 5-7 minutes off those times if the window motor has been changed before.
Last TA i did was being a bitch and took almost 2 hours..

But have fun.. good luck, say a quick prayer and bring lots of beer to help the mechanic thought process.