96 Monte New Engine or Cam

I've been given a Monte Carlo that hasn't been driven in 2 years. The car is in great shape (except for the engine obviously) so it'll be worth the effort. 2 years ago when I broke down, the owner was told it needs a new cam. I do not understand how a car can need a new cam?? I'm thinking because it has sat for 2 years, just do a whole engine swap. What do you think? I have no idea where to begin. Cam or Engine? Any reliable sources for the engine?

Scott