Be careful,
Many of the "SS"'s are actually faked out 402's (which are nice as well). A true SS will have the boxed rear control arms and the load leveler system (or at least, what may be left of it, hoses etc). Also the SS's were only made in 70 and 71, in 72 they did have a 454 option, but it was a "custom", and could also come in a 350 version.
Try
www.firstgenerationmontecarlo.com, really a cool bunch of guys and have forgot more than I know about fir gen Monte's!
Rich
All in all, cool cars