The cooling system design on an LS engine seems to work best with a radiator that has both the inlet and outlet on the passenger side. Many companies like BeCool, Flex-A-Lite, AutoRad, and the AFCO radiator shown here offer these cross-flow units just for LS swap applications. In addition to the packaging benefits, there are also cooling benefits to the cross-flow design. Guys with more determination than cash can source a good candidate from a salvage yard. It won't be pretty, but it will work.