Actually, yes the plan is to make the space in to a room, perhaps a bedroom. The local code here says 38 cm minimum opening dimension and .35 sq m for the open area. The existing window is a double slider about 1.5 times the allowable limit assuming the opening portion can be satisfied by lifting the sliding panes out of the frame. I would rather have a style that opens all the way without removing the glass and a larger size to let more light in. It is tricky to decide. Swinging out on the bottom means the window could get blocked by ice and snow, swing in might allow me to bump my head, maybe if they exist a swing in with the opeing at the top might work. Anyway, that's the idea.
The third option for the lintel is a steel beam cemented in to the top course of block...maybe with a lower height than the existing 8inch high cement lintel to give me a larger opening. The trick is sizing the beam...most tables assume larger spans than 3 feet and longer joists span than I have. The minimum for wood is 3 2x8.
Thanks for your reply.