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)

[ClayPerrine]

From experience...

I have a 2.4 ST motor (S cams, S pistons and cylinders, T heads) that I took out of my six conversion for the 4.0. With an HB fifth gear, I could not run at 60mph. The fan was too slow to keep it cool in fifth, and it would overheat spinning it in 4th. I switched fifth for a ZD, and was able to keep it close to cool. I put a 911 Carrera cooler in the left rear corner next to the muffler and sway bar, and it dropped the temps by about 80 degrees. You may not experience that in Boulder, but it was definitely needed in Texas.

If you make that engine a 2.4, you will have to run premium gas, and you will need to look at a twin plug setup. The compression using 2.2S pistons and a 70.4mm stroke comes out to about 10 to 1. Great performer, but not a great street car. And you will definitely need some sort of external oil cooler on it. If you can afford it, Elephant racing sells a set of front oil cooler lines, and the coolers to go with them.

Clay