Gets hot and stalls out

You need to get an IR temp gun and hit the temp of the top tank where the upper hose goes in and then hit the bottom tank where the hose comes out and see how efficient that radiator is. Just because it's new and shiny doesn't mean it's good. A lot of times, the further away you get from stock, the worse these problems become. Remember, there were factory STOCK engines that put out way more power than what you have running totally STOCK cooling systems. You have something WRONG.