360 vacuum leak.

I have a 77 360 with a Carter AFB style carb, headers, and performer intake, and I believe I have a vacuum leak from my breather caps/ PCV setup. Currently the passenger side has a breather AND the PCV valve and the drivers has a breather. I read that there's not supposed to be a breather on the side with the pcv so just to test if this was the source of my vacuum problems i took the pcv off and capped it and the carb port. When I ran the engine like this it ran extremely rough and died. When I connect the PCV it runs as good as usual. Im planning on getting new valve covers and just running one side PCV and one breather but I'm wondering if this is normal behavior? Does the carb just need to be retuned if I run no PCV?