The plural heads here in Jacob 1:4 seems strange to today’s English readers, although it is not difficult from the context to guess that it means something like ‘the main points’. The Oxford English Dictionary lists the meaning ‘one of the chief points of a discourse’ for the noun head (under definition 27) and gives the following citations with the plural heads (here cited with original accidentals):
A related meaning for head under this same definition 27 is ‘category’. A common use is the expression “under this head”, as in the following OED citation:
The same meaning of ‘category’ for head is found in the Book of Mormon, and in each case the verb call is used to specify the category:
In the first instance, the category is “the children of Christ”; in the second, it is “the Lamanites”. The critical text will maintain these unusual uses of the word head. The printed editions have also maintained these instances of head, despite their difficulty for modern readers.
Summary: Maintain in Jacob 1:4, Mosiah 5:8, and Alma 3:10 the word head with its archaic meanings ‘main point’ and ‘category’.