How do you all know where the OP is located? I am assuming Europe, finding a used Frommia saw in the US would be difficult to say the least, but pretty cool.

Personally, I would check to see that the modern version of that frame size (90L) motor has the same bolt hole pattern and shaft size (they should). If that's the case, I would find another 1400rpm version and use that.

In a 90L frame you can get 2.2kW which would be a decent upgrade from the 1.5kW.

I would probably get a 3ph motor and run it with a VFD if you don't have 3ph, that way you can adjust the speed a bit.