My L Motor EGTs run about 1650-1700 - 3.0L, T66, 7.8:1 compression, ~ 20PSI boost, ~ 430 whp. I have not been able to decrease this with fuel or timing adjustments.
I was alarmed by this number until hearing of others' results...
I concur with Tim and others here that think that big cam specs are responsible for the higher EGTs. My cam is 274 duration/.515 lift intake, 266/.490 exhaust, 114* lobe center. I'm no cam expert, but believe that even with the relatively low duration and wide lobe center, the net overlap of the bigger cam is greatly increased over stock, allowing more "blow-through" of unburned fuel.
I don't see much discussion of probe position, but my probe is located at the turbine inlet about 6" away from the nearest exhaust valve. My old BAE manifold appears to have shorter runners than the L28 stocker.
Sadly, I've not looked at EGTs until my engine build has progressed to this point - I would have been instructive to see what numbers the earlier, milder builds would have produced, and what changes occurred when the various mods were done.