Yea, 4 inch screws are likely going to be to long. You don't want the screw to come through the other side!!
Like Graphic said 2x4's are not 2 inches x 4 inches. They are smaller. I think you will be better off with 2 1/2 inch screws, 3 at the most.
Like Graphic said 2x4's are not 2 inches x 4 inches. They are smaller. I think you will be better off with 2 1/2 inch screws, 3 at the most.
