Is it possible to weld a bit of threaded bar to the stub thats left, i am sure a welder can come up with something, i take it thats the underside of the exhaust.
Maybe, but not being able to weld or no any welders it would probably be cheaper just to by a used one. I'm wondering if it can be removed and another inserted or if it's a sealed unit.
My Motrax plate mounting thingy doesn't use these bolts. I'm sure there must be others that don't either.