71 Dodge Dart Swinger in England

TBH just had the same thought, for now I'll slave in the GM HEI with a simple wiring loom to the battery. HEI on a heatsink that is earthed.
Something that is going through my mind is could the pickup coil be reverse wired? sure ive read that somewhere, the wires off it are black and gray. Can it be checked? I assume black pickup wire will go to pin G and gray to pin W on the GM HEI module.

Out of a elimination I may also buy a new pickup and reluctor.

re checked the timing and on tickover with vac off its 8 Deg, with vac connected its 22 deg and at approx 2500 rpm (ish) max mech advance ( with vac connected )its approx 44 deg.

Checked the phasing by drilling hole in old cap, seems to be about right , its not centred on the pin but only slightly to the side and retards back when vac attached. I might re check tomorrow to note the position either side of the cap post.