That looks like a heck of a find. Thats a fairly upscale bike. Post a drive side photo so we can see what it is a bit better.
Looks like Super Mity cranks, Suntour ARX derailleurs, Suntour Powershifts (probably the best pre index down tube shifters ever).
What dos the seat tube and forks stickers say its made out of?
Id guess that to be about 83. Here is how to date the bits like the Derailleurs : http://www.vintage-trek.com/component_dates.htm#suntour
It will give you a rough idea of the vintage as long as the stock was being rotated. parts dated mid to late year usually mean to date the bike as the next model year.