I think the hose is actually 40mm by the book, which is a hair under 1.5".

I just went to the local PEP boys, found a hose with a straight section the same diameter, and put it back on.

The factory clamps both had corroded screws so I put some BREEZE constant spring tension clamps on there.

One bolt was really rusty and should have been replaced. I think this comes from coolant leaking into the bolt hole. The other bolt was shiny.

So order new bolts and clamps and a new thermostat and gasket before you take it loose. And maybe all the other radiator hoses if they are old. Cheap insurance against a head replacement.