I’ve put two on scales that went 384 and 374. They were enormous. I’ve likely killed one that was 400# or over, but I can’t say that with certainty simply because I didn’t weigh it, and where it was, I wasn’t going to even try to get it out.
With that said, I’ve killed thousands of hogs in several counties and those were the only 3 I know of that were larger than average. A big average boar is 200-225 lbs.