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Photos of air cleaner will work as shown. The top part with silencer is not required for proper air cleaning. However, if you aren't concerned with original appearance, you might get a small after-market paper air cleaner, which will make for less mess, and will make carb easier to access without removing the air cleaner. For originality, keep an eye out for the top portion with silencer. A bracket that attaches to outer end of silencer and to head bolt is also needed.
The '55 from Sirrotica's video doesn't have the silencer, but it is the "standard" 2-barrel carb. From what I'm seeing in the MPC, Group 3.402, only the "heavy duty" air cleaner with silencer was used for 4-barrel carb. The 4-barrel carb was not available until the "power pack" option was released, mid-year '55.
Question 1. How does air cleaner work? See Shop Manual, p. 6B-2. For air cleaner maintenance, see p. 0-5. Use engine oil.
Question 2. Use the green IAT antifreeze at 50/50 ratio with water. Distilled water is best. Additional additives not needed. For details, see
https://www.hemmings.com/stories/tec...of-antifreeze/