The turbocompressor inlets on the DC-8 nose (-10 through -60 series models) are equivalent to the inlets at the front of the engine pylons on 707s where the turbocmpressors are in the pylons of engines 2/3/4. The 720 only has 2 turbocmpressors above engines 2 and 3. AA also ordered their 707s with only 2 turbocompressors, thus the narrow pylon on engine #4 on AA 707s. I believe a very few other 707s may have been built with only 2 turbocompressors.
707s with the usual 3 turbocompressors on engines 2/3/4 and the narrow pylon on #1.