A club buddy (very experienced in giant scale construction and flying) put a Fuji 64 in his big P-47. Today, while adjusting the high end needle to get it running smoothly, someone else checked the head with an IR temp gauge and we got a reading of 280 degrees, so the engine was shut down. It's being run with a 25:1 oil ratio, and it's not too lean. We feel that there is enough cutouts in the dummy radial to get suffiecient cooling air to it; however, we'll remove the cowl and try it again. But what would an appropriate head temperature be for this engine at full throttle?

We don't have a number for cylinder head temperatures. We simply don't use them. We adjust the engine by how it's running. With a 25:1 fuel/oil mixture, you have plenty of lubrication. As long as the engine is set rich of peak RPM, and is running well, your temps will be OK, no matter where they wind up.

Again, we don't use temps at all to set the engine. Maybe once we've found the setting that works, we'll check a temp out of curiosity, but we don't use it to confirm whether a setting is "good" or not.