Awhile ago, I tried searching for a general, all-purpose, "muscle car" website that had info and forums on all the popular muscle cars from the 60's and early 70's. Something akin to Car-Craft and Popular Hot Rod magazines, but on the internet. Unfortunately, I didn't find anything like that. But I did find a few websites that had info on specific model and make muscle cars, such as the Mustang and some Mopar models. If you're into older Mustangs (64 - 73), try the forum at stangnet.com . Unfortunately, I don't remember the Mopar website, but the one I found had some interesting info on the different Mopar models, including the Hemi.
If you find anything more, please let me know because I'm also interested in learning more about those cars. Take care,
Ed Q.