Justice If possible would stay with original wiring it is plenty heavy for 12 volt,as kevinski said. Install a 1-wire alternator it only ttakes 3 wires to the rear of the truck to get everything done if you use a 9 wire turn signal switch. Your starter will work fine as is really whip over,change bulbs to 12 v and you've pretty well got it done. Might add a few fuses. The trouble with wiring harness is you have the firewall insulation in the way and other obstacles. The Guide brand turn signal switch (which is what the chevy dealer would have put in) works good ,may be kind of hard to land one not as many around now. Good Luck with your truck,we'll help as best we can !!
