General question on vacuum...

Newly-installed six pack won't hold idle below 1,300 RPM in neutral. I'm thinking may be vacuum leak, but increasing RPMs usually signal a vacuum leak, correct? Did not have chance to spray carb cleaner, etc. around manifold surface and carb gaskets.

Butterflies are fully closed in outer carbs, linkage is set, 2 turns out on idle screws on center, 1 turn out on idle set screw (from "square transfer slot setting" in the "unofficial six pack tuning guide on Moparts).

Thoughts?

"1 turn out on idle set screw " if this means the mixture screws on the base of the outboards then that is too much. between an 1/8 and a 1/4 is a good starting point. do your check for a vacuum leak all along the bases and your intake runners.

Sure sounds like classic vac leak