^^^X2 - I can get better results with EGR delete and adding HLC (Hyway Lean Cruise) which adds more SA and leans out AFR to ~16.7 with no KCs.It's a bandaid is what it is. Later motors with better cats and cams with different profiles (which reduce cylinder pressures/NOx) managed to get by without EGR.
I also replaced my old 2-way cat with a newer 3-way that does reduce NOx.