Engine simulators (and starting to see the box as a expanding circle!)

Anyways, I feel that one tool that I could start using is an engine simulator. My background in physics/mathematics is really not strong. (going back to school) I have a few ideas on what books I want to pick up but any suggestions would be fantastic. I have an old "how to build a ls1" that needs a good dusting but I feel that I want to just know more, quintessentially.
So, as for an engine simulator, which one would ya'll recommend? Furthermore, considering the ProRacing Sim softwares such as dynomation 5, how accurate are these sims when taking something "built" in the sim and applying to it in the real world? I can assume that they have been doing for a long time and they wouldn't be in business if they had a flawed system.
So, engine guru's, be gentle! What I'm asking for is a nudge, or a shove if you feel so inclined, in the right direction. We all start somewhere.
thanks.



