How hot are we talking here?

I think the engines are meant to run around the 260-280 range, which is bloody hot!

Know anyone with one of those temperature measuring gizmo's to try it out?

If not, there's always the spit test - put a drop of water on the head when your engine gets warm. It should take 5-7 seconds to evaporate. If it boils straight off, you're too lean. If it takes longer, you're too rich.