from not only other BB'ers but also Cameron at IPD himself, that they can't really get good headers for 140s... and what not. But OTOH I've heard that the V-perf's swedish headers are really good, I don't know anything about fitment, but they are good performance headers. You can as John Parker (I think that's his name, at V-Perf.) and he'll prolly be able to recommend a good header that he sells, and he will be able to help you determine which primary tube size you might want to use along with your "head work". Hope this helps!
Later,
Kyle

P.S. I have no connection with any company listed.... If that really matters anyway. I've just seen someone else say that they have no affiliation with them, so I decided I'd do the same... ;-)