Legality seems fine, no one has put a a reasonable reason why not yet.
Jets have a box full, bell seem to be the same, intake is tighter but supect that how any 38mm would be going up from a 34, but it does fit in. only thing i can see is the plumbing and internally differant journals, and bowl is differant set up maybe cause motor its enclosed or frost risk. hell who knows but they seem to work.