Where in the actual novel (chapter number, etc.) can I locate Faulkner's longest sentence (1,287 words) in "Absalom, Absalom?"?
OK, I found it for you. It's on page 361 of the corrected text Modern Library edition. You can actually read some of the sentence online at Amazon, which has a search inside the book feature.
I would recommend a flip through the book. I know the sentence goes on for a couple of pages and found that it begins with "They bore it as though..."