I agree with poly...you are getting to the point of diminishing returns.

The good news is oil control will be better and that equals some HP. As to how much more HP you will gain from more than 13 inches of vacuum it will be some but probably not more than 10 or so.

I don't know your displacement and I'm not sure if you are running a crank scraper. You may want to call Kevin Johnson at Ishahara-Johnson cranks scrapers. Not only can he tell you if he thinks a scraper will help he is a sharp guy when it comes to oil issues.