First question is do you have the wiring diagram from the manual if not see
http://www.canadianregister.co.uk/do...ordmanual.html unlike the Chevy manual it does not list the wire sizes like the Chevy manual
http://www.canadianregister.co.uk/do...evymanual.html in comparing the wiring diagrams I noted that for some reason it looks like they used different wire color trace patterns. The instrument panel wiring on the Chevs is listed as 16 gage though some of it is much heavier so look at the logic of the loads carried.