I love the old Monte's.
Great site here for them:
http://www.firstgenmc.com/
I have had several, a SS454 and an uber rare BB 402 4-speed Monte.
Great, fun cars with no resale value at all I am sorry to say. I would say that is a 12k car all day and night, possibly as much as 15 if you were keeping it and not trying to resell anytime soon.
Fun fact on the 70 and 71 Monte's. If you look at the grill emblem, you will see the knights helmet. In Roman numerals on the crest of the helmet will be the year of production, spelled out in roman numerals.
http://www.firstgenmc.com/tech/differences.shtml
Rich