Staying Mustang focused, 1967 was the first year with a vacuum reservoir, for integral A/C, tilt-away steering column, or both. Attached are listings of reservoirs (sometimes called vacuum cans or vacuum canisters, noting that here to support future searches) for 67 and 68. Also is a picture of what I believe to the the oblong C7ZZ-19A566-A. The C9ZZ-3E547-A picture is premature from a 67-68 perspective, but I wanted to include it to show the "coffee can" shape. Note that I purchased this new at the Ford dealer in 1981 as a replacement for the C7ZZ-3E547-A that I was looking for. I was disappointed to see that one of the vacuum ports was much smaller than original.