Hi Allfie
I am using a US sourced motor from a GTO Pontiac (Holden Monaro). The wiring loom and ECU are different than the Aussie Holden Monaro however and Holden were not interested in giving me any wiring info so in the end I found a web site called alldatadiy.com that has all electrical/ mechanical diagrams for USA cars ($28 US to join, email me and I can give you my access code). The VDO guages I am using use either inputs from the ECU ie Tacho and Speedo or direct from the motor/body sensors ie fuel level guage,
oil pressure, water temp, volts. I am using a 15 circuit harness from American Autowire and a very tidy fuse, relay box harness to power the motor harness and 15 circuit harness from a company ez2wire in the States.
I am finding the electrical puzzle quite enjoyable.
Bruce