GAS FURNACE VENTING QUESTION> - While having some work done on my exterior foundation, both the intake and vent pipes from my gas furnace (Keeprite N9MP2100) were cutoff where they horizontally exit the wall of the house. They are now about 6 inches long. Should either pipe have a 90 degree end on it to prevent contamination/condensation etc, and which way should that end point (up/down/ sideways awy from the other)? Thanks for any thoughts.

Install a 45 degree elbow on each pipe, pointing down so they are 90 degrees apart. I usually install a piece of 1/8" screen mesh in the throat of the elbow. It keeps wasps from building nests in the pipes.