info on +ve to -ve conversion requested

["Evangelos G. Makris" <emakris@hol.gr>]

Where can I find information on how to convert from +ve
ground to -ve *and* from dynamo/control box to alternator
at the same time?

The +ve ground car has an ammeter, voltmeter, non-lit fuel
gauge, but thankfully the tacho is the mechanical type (all Smiths).

Will these instruments need any rewiring, how about
the heater booster motor and wiper motor?

The fusebox is the classic 2-fuse Lucas type.

Thank you
Evangelos