My house was built in 1939. Most radiators are 4 tubes with various sand number of sections. What is annoying is that the supply and return pipings inlets to the radiator are side by side, on the same side, at the bottom of the radiator. The heating system is still hot water gravity - two pipes and it works OK!

I contemplate the conversion from gravity heating to hot water forced circulation with the removal of all existing large pipes in the basement. Would the cast iron radiators with the side-by-side supply and return piping work in a circulated system? How should one approach the design of the new system with such radiators?

Any help will be appreciated!