I took the SAT the last year before they changed it. Got 800 verbal and 750 math. My husband is a year older, so also took the old test, and he got the same score but reversed (his perfect score was in math). I don’t know about Jewish kids in general, but I suppose they curve out about the same as the general population. There’s an old urban legend that the frum kids get a harder test (the SAT is always on a Shabbos, so frum Jews and Seventh Day Adventists have to sign up for the alternate test on Sunday) but I don’t think that’s true.
I also don’t think any schools teach to the test. It’s just that more affluent kids (as non-frum Jews tend to be) go to better schools in general and their parents can afford pricey test prep services.
I actually worked for Kaplan Test Prep for a while- they invite anyone with high SAT scores to “audition” for a teaching job. I don’t work there anymore, but thanks to the training I got, I am known in my neighborhood for SAT tutoring- unlike other tutors, these are not a dime a dozen, so I always have work, and it makes for a nice bit of extra cash.