Idle screw question. Rich or lean?

friends car. Not Mopar. But helping cause I like v8s.

Holley 4160 (new). Stock small block... No emissions stuff. Trying to get idle dialed in. Steady vac at about 19. Idles pretty consistent. But when you clutch in coming to a light, the idle dips low and comes back up.

Is that a needs to be a bit richer or leaner on the idle screws ? Seems in my mind when the plates shut it can't get enough fuel right away and goes lean...but I dunno.