The honest truth, find yourself a dyno operator that does know what he is doing, as the emissions should be a massive clue, the ht leads can indeed cause interference particularly so with the cps wiring which is why this is shielded to earth at one end, just keep so it is not touching and away by 4-5" will be fine.
I would try some IK31 plus at that boost personally, gapped to 0.8 as you have a msd coil, but you want to check the resistance of this coil and comapre with the ignition amp as well.
Fuel pressure needs checking as does fuel filter(changing) and a pump rewire just to rule these out and because they are needed anyway on any cossie now due to age.
what is the duty cycle of the injectors at max power.
tabetha