Cruise Seems Lean

IIRC the 1850 metering blocks (the 600 vacuum secondary carb) will work. I would pin the emulsion and idle feed restriction and see where they are at. I’m certain the idle feeds will be smaller and that’s probably not a bad thing.
YR - food for thought
Would possibly Holley have a block with replaceable air bleeds?
If so, that's what I would source.