I had a 2.1 pinto running around 180 through the std 1600 mk2 rad, was a new rad, but as far as I can remember std, I was more meaning the principle, it can be done without a expansion tank rather than be safe with a std 1600 rad, the mk2 has a massive frontal area for cooling compared with most modern/ish cars so that helps, could just get a thicker core one made ?
tabetha