[casioqv]

I think the 260 series V6 Volvos had the same radiator. If you can get a used brass radiator, an old school radiator shop can re-core it, essentially reusing the end tanks to build you a new radiator.

You could also look at switching over to a brand new 4 cylinder gasoline radiator, if you could find a good solution to make the hoses line up properly. It's a smaller radiator, but actually seems to cool better and clog less often. They adequately cool the B230FT motors which easily produce more than twice the heat of a D24.

Despite producing more heat, the gasoline Volvos run cooler uphill, probably because they climb faster and get more airflow over the radiator. If you go with a smaller radiator, just make sure you have all of the plastic shrouds properly in place, and a very good fan (ideally a brand new Aisin tropical fan clutch).