With the early Hemis; Chrysler had three, Dodge had four, DeSoto had four, and Plymouth had ZERO, for a total of eleven. Plus, the 426 (twelve), the 5.7L, 6.1L and the modern 392 ci Hemi (6.4L, all actually Polys!) for a total of fifteen. Add to that, the four-cylinder 2.6L Mitsu Hemi used in the '80s, now were are at sixteen. The Aussie six-cylinder Hemi counts, too. Seventeen, so far. Anyone else??? Feel free to add to this, because I know I missed at least one.
The Chrysler Industrial Hemis were available in just two flavors - 331 and 354.