They are probably RS-380PH-3270
. This motor has maximum efficiency at about 2A, and needs 14V to match the performance of a 6V Speed 400 at 7V.
They could be useful in a large multi-engined model, eg. a B-36 Peacemaker might have 6 motors running on 16 cells, drawing about 30A total. The advantage of high voltage motors is that they can all be wired in parallel, which is more reliable and less complicated than a series/parallel combination.