Silver tries to be transparent about his model. For a non- technical description, see [1]. He used to have something more technical/concrete on his personal blog. I'm guessing you can still find that easily.
The fact that he doesn't include specific equations in his NYTimes blog is likely only to improve accessibility to non-technical readers.
That said, he has given enough detail for others to roughly replicate his work. See [2]
You substantially underestimate the effect of the (unreported) model parameters. A person can often arbitrarily change the prediction by tweaking the parameters.
Thank you for the link to the attempt to reproduce Silver's results. I will have to spend more time to determine how closely they agree -- it isn't obvious after a cursory look.
The fact that he doesn't include specific equations in his NYTimes blog is likely only to improve accessibility to non-technical readers.
That said, he has given enough detail for others to roughly replicate his work. See [2]
[1] http://fivethirtyeight.blogs.nytimes.com/methodology/
[2] https://github.com/jseabold/538model