I use Weil-McLain cast iron boilers, don't care for their wall hung mod-cons. Weil-McLain CG series for hot water, EG series for steam. No more standing pilot available (Have to get that .5 of efficiency) Do a heat loss for the house- 140,000 sounds high unless a really, really big house. Slant-Fin has free app, not too hard to use.
If hot water system, size the boiler to the heat loss, if steam size to the radiation.