The only parts in your pumps and distributor that are polarity sensitive are the electronics, so 90% of what you have is just fine. You simply need to replace the electronic modules with ones with the correct polarity. I would be very surprised if Pertronix wouldn’t be able to provide you with the correct part to change the distributor over to negative ground. I don’t know the specific design of the fuel pump, but if it uses points then you could simply install one of Marek’s boards.