if running 205 at 70 degrees, then what would you be running at if
outside temp was 90 degrees. 225? Then what will eng temp do if you
are at 90 degrees outside, but stuck in traffic, at idle for 5 minutes. At idle you have very
slow coolant flow. The hotter you get you might start developing some vapor pockets/hot spots in your heads, which normally
I've read have about 15 degrees hotter watar than the water going to your radiator. A weak coolant pump can
give poor flow in the heads. Aluminum heads like/don't mind hot, because they transfer heat very well, but iron heads don't transfer heat as well,
and that can contribute to detonation. Bottom line, give yourself as much margin possible, without
negativly affecting engine performance. An Aluminum radiator is a great way to get that margin.