Reading may single-handedly account for the disparity between those who are good test takers and those who are not. Reading is one of those things that people "don't have the time for." But if you are able to fit reading into your schedule, then more power to you. I can understand if you only have a few months to study for your exam that reading will not be on your priority list. I agree that at that point in time, reading a book or two will not significantly change your reading comprehension or reading pace. What it will do, is provide some more fodder for your SAT or ACT essay. This is why getting an early start on reading is key - take a look at my thoughts on some books.
Reading
List (part one) - Harry Potter flew over the
Cuckoo's Nest.