I have a Lycoming IO 360 A1A and have flown behind it for many hours. I decided that I wanted to know CHT and EGT temperatures since the engine is injected. I installed four posistion CHT and EGT guages and cranked the engine. After running at about 1200 rpm for several minutes the CHTs settled at about 300 degrees farenheit. The EGTs were questionable...hence my question. They settled at 850 degrees for #1 and #3 and about 1250 degrees for #2 and #4. The CHTs were very close at 300 degrees but quite a difference with the EGTs. The airplane was obviously not flying. What should the EGT temperatures be in this particular situation? I pulled the injectors out and checked for obstructions, but they were as clean as could be.