A 1 1/2" to 1 3/4" exhaust pipe reducer, with suitable radiator hose clamped on either end would work.
Cut the end off the stock radiator hose and find a 1 3/4" hose with the right bend in it for the end.
Or see if a radiator shop cad weld an aluminum reducer on it.
"We can choose to know better or choose to be bitter." OldRoadToad