At what displacement are external coolers needed?, Building an alternative engine for my six Options

[Speedo]

I have read that the general consensus is above 180 hp an external cooler is needed.
I am at a crossroads with the 2.2 T I am building. I have 2.2 S pistons and cylinders and and cams. If I stroke it I get a higher cr 2.4 S. If I don't stroke it I get a decent 2.2 S which would still be a nice choice. I have everything I need for the 2.2, but if I stroke it I will need to source a 70.4 crank. Curious what the board thinks about the "red line in the sand" for needing cooling. It goes without saying that I am not interested in cutting on the six for a cooler up front.
Having said that...I spoke with a friend over the weekend with a 76 911 with a 3.2 transplant that doesn't run a cooler. He says his temps never go over 210...which I question as I have a stock 74 2.7 with a modified pulley setup that runs 200 but will show 230 when pushed. I think I need to measure his temps with a pyrometer to double check his temp gauge. (IMG:style_emoticons/default/bs.gif)
Tell me what you guys think! (IMG:style_emoticons/default/idea.gif)

[Steve]

Prior to my 3.2, I had a 2.7. The 2.7 ran hotter than the 3.2. Over stressed magnesium case versus under stressed aluminum case. My 3.2 front cooler thermostat only comes on when I’m stuck in traffic in the middle of summer in so cal.