Low vacuum - should I ditch my vacuum advance distributor?

You always use a vacuum advance until you can’t. And that largely depends on compression ratio and cam timing. Not running vacuum advance is bad policy for most anything that sees street time.

I‘ll be 12:1 on pump gas and I’m going to see if I can use vacuum advance. It will take less fuel, run cooler and make more power at cruise RPM. It’s a win-win IF I can make it happen.