As I remember, the SUs used on the Volvos were actually smaller than those used on TRs. In addition, they used needles that were of a completely different taper. (Obviously, that's a really easy swap to get the right needles in there.)
Now, I actually have seen Triumphs and Datsuns with SUs sourced from Volvos -- but it has been a very, very long time.
Given the nature of the HS6, I can imagine that one can adjust the angle of the float bowl with a little tinkering.