340 dyno chart thoughts

I do not know why all you guys run such low idle vacuum numbers. I have a 360- 410 stroker in my aussie charger. It has a hughes 228-232 roller cam in it with 800 edelbrock carb with RPM air gap manifold. Vacuum is 14 @850 revs and 15 @ 1000revs. Plenty for power brakes to work well. I am thinking of putting one of those adjustable PCV valves on it . Anyone with a link to the manufacturer of these.