If your used to glow, You'll find the gassers run a bit hotter (it seems) than glow engines.
You won't overheat with an 18x8. I've found that's the best size prop to run on my twin-ring ryobis.

The bigger concern for these motors is under propping and excceding max RPMs of about 9000 with the stamped steel con-rod.
(which you won't do with that prop)

One nice thing about the heat though...with the right muffler.......they SURE DO MAKE NICE SMOKE!!!

Sorry I don't have temps, but I'd like to see some readings on other people's temps too...

CrazyHerb