good question. I know NOx formations happen at high temps (so they dilute it with cooler EGR ) but I think those events are so short that the heat is immediately quashed by the inrush of: cold fuel, inlet air, and EGR so the average temp is well within the AL working zone. Also with the EGR and EFI, exhaust temps are probably very tightly controlled. Temps would be a little looser with a 1920 Holley but were still talking a 7.5:1 110HP slant.
