Interesting info. So the torque is dropping off at the same rate that the revs increase from 6800 to 7100. I can't imagine why the power would rise right at the end. I presume there would have to be better cylinder filling - perhaps a lucky consequence of the inlet and exhaust designs at that rpm.
The grand plan that is under consideration here is that I want to replicate the look and feel of the Dino engine. Interestingly, although the 12V Dino engine is very oversquare and delivers max power (about 190 bhp) at 7200 (the start of the yellow area on the tacho), it makes maximum torque at only 4000 rpm. This is 1000 rpm less than the Alfa 24V which produces almost exactly the same power as the Dino but at less revs. I presume this is a characteristic of it being a 24V engine, amongst other things.
I'm considering making an inlet manifold to mount carburettors and also would need to look for a way to mount a distributor. There would then be no modern electronics to act as a rev limiter unless I add something electronic on for safety. In the first place I could just go to carbs and leave the ecu connected to control ignition. My kit car was registered long ago enough for a replacement engine to be able to run without catalytic converters and it also has very relaxed emissions requirements (either no dense smoke visible or less than 4.5% CO and 1200 ppm HC, depending on the person who tests it!).