$10K ? Having never made one of these, this may seem out of line, but one can get an aluminum head for way under that, under $1,000 and that is for a production run under 10 where the universal supply and demand is incredibly limited. My guess is that a head is much more complicated than a bell housing. Assuming the costs are much lower, is there anyone out there able to advise if the bell housing is the major factor / major part?