Yes the tr7 has a seperate bellhousing,but I have never heard of any one using it for a tr3 conversion. Tranny swaps are mostly a question diamentions of the box vs what you had,get pretty close and the problems are fewer. From what I have heard, the toyota box is a very easy swap and cheap to find.Most of the $$ is in the kit, if they ever come down a bit they could be really popular!!
MD(mad dog)