Sounds like a possible solution to your high idle problem. Hope so!
If, as you said, all the throttle shafts will turn so that the throttle plates seem to close so as to seat in their bores, that's GooD!
________________________
I'm trying to think of possible variables in carburetor rebuilding work...
- For many years in production engine assembly, pistons were selectively fit because of machining variations.
- Your carburetors have likely been apart more than once since they were produced ~57 years ago.
- I wonder IF the throttle plates were originally selectively fit in Holley 4000 carburetors when they were manufactured?
- IF the throttle plates were originally individually fit, I wonder how meticulously someone kept track of their original locations when they were torn down and reassembled over the past 5+ decades...
________________________
Let us know how you make out!
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York