Without the measurement of the indicated pressure in the cylinder it is hard to say anything. But thanks for your reply. I belive, that 500ps is possible. Many people drive 600 to 800ps some years without problems. However we must take care, if the ignition is in a good state and the distance of the spark plags is not too big.
3B Motor with the ignition distributor in the race UrQuattro in 80´s had also about 500ps...
Maybe it could also help a bit, if the main cable has no electrical resistance. Is there something with 0 ohm or with a small electrical resistance on the market?
That resistance is completely irrelevant in the grand scheme of things. All your theorycraft about "resistance" is irrelevant as well.
It only matters that you have the correct distributor and correct spark gap. And you will not have any issues at even 600hp.