Your booster should also have a check valve on it's input to retain booster vacuum even under heavy acceleration. This is the standard set up on most vehicles so you shouldn't have any problems. Since you're running HEI I assume you're on 12V so you could also get a vacuum pump instead of using engine vacuum. Also a fuel/vacuum pump may get the job done. They were originally used for wipers. I don't have one so I don't know how effective they are. Good luck!
