DavidM wrote:
The 1920's Packard "air valve" type carburetor has two air entry ports making it difficult to fit an air cleaner. Packard offered such an air cleaner in 1928 as a retrofit item. See attached letter dated August 15 1928.
A few of these air cleaners were reproduced here in Australia many years ago and I was able to find one and fit it to my 633, see photo. It comprised two castings. Unfortunately, the patterns were left with a foundry that later closed, and the patterns have been lost.