1985 Trek 400 built up to commute on this year. I changed out the 27" wheels for 700c Matrix/Campy wheels from ebay (probably came from a higher-end Trek with Trek SS spokes). Also replaced the brakes with Tektros and Tektro aero levers, shifters are Suntour Power Shifters, and the rear derailleur will probably be swapped for a Suntour Cyclone. Sunrace 13-25 7 speed freewheel and SRAM 8 speed chain.
This is my first Trek, and even though it is a lower model, I am impressed with how much bike you got for the money. Double-butted True Temper frame, lugged on a base model?