New 408 stroker runs rough at idle

Moparmadness408 said
is the vacuum readings you mention at sea level? I’m getting 7-8 inches at 5000 feet above sea level.

We're at 2150.
You loose approx 1 inch per 1000. But our ratings are conservative. Your reading still feels low.
Will it rev clean once you get it to "catch up" and pass the stumble?
What do your plugs look like?
What is total timing at?