I took out a kitchen wall which contained one of my cold air returns (Upstate NY heat & AC), I'm putting in a hardwood floor and wonder if I can just place the return in the basement. The house is a split with air flow open to all four levels.I don't heat the basement but the open plan keeps it around 60 degrees in the winter.

By placing the return air grille in the basement, you will be creating negative pressure down there, which will draw your expensively-heated air out of your house and down to the basement. I don't think relocating it to the basement is a good idea.

Was that grille ducted directly to the furnace, or was it simply open to the furnace room? Either way, I'd try to find another location for it.

Richard is right. Putting the return air in the basement is a bad idea. It won't heat the house nearly as good. You need atleast one return air vent on each floor that is heated/cooled.

Thank you both ! Plan 2 is to move it across the room to a side wall against the wishes of my wife. But she pays the bills so I'll argue cost. It is directly ducted to the furnace.

Not that I want to start a arguement, but it seems that wifes don't want to do it right if it interfers with their plans(or the final look outcome). Husbands are easier to convince that something needs to be done differently.