Sounds like a mental engine mate! My 1.8 blacktop is pretty lightweight compared to that but commenting on what my graph showed (standard comp and pistons, standard head, stage 2 cams) I get a constantly climbing power curve with a dip in power and torque at 3500rpm (well known flat spot) and slightly before at around 2500rpm. After about 3800rpm torque peaks and holds and power constantly on the increase till the limiter. Hope that's of some help as N/A zetecs somehow all display some form of torque dip in the mid range, even one that was on OMEX..

Can you post up your curve please? Otherwise very impressive motor it sounds like you got there!