You most likely have a failed sender. If you were pushing 2000deg you are at meltdown temps.
From the SBMAR web site. A great resource . Tony Athens
"If you look at all of the various 6BTA models rated from the early 300 ( CPL 970/1613) thru the latest CPL 8457 (370 Diamond), published EGT’s run from about 850F thru 920 F at WOT/full engine loading. Remember, these numbers are taken is certified test cells and are there for a guide..
Engine room conditions are far from test cell conditions as to everything that affects engine performance, and these engine specs are on NEW ENGINES..
Field experience has told me most installs run higher than these specs– May 25F-100F and still to me, this is normal.. And something running below WOT can product higher EGT’s than at full RPM–Lot’s of variables in how each boat can load an engine.
So back to your question– Maybe once the vessel is on a clean plane at 2000-2400 RPM–900-950 F-ish? Running below 900F is always a good thing, but very “propped out” early B’s do that.
How long have been watching the EGT? An established base line is good when all is in good shape & up to spec, especially the aftercooler and the turbo..A turbo that has been eating saltwater just about always lowers boost and raises EGT. A dirty aftercooler also does the same."