Headlight section of harness.

I'm pretty sure the headlight harness runs along the driver's inner fender with the rest of the harness, then should pass through a hole in the core support, under the lip on the outside (Front) of the core support over to the right headlight/parking & side marker lights. I believe the alt wire runs along the top of the engine between the valve cover & intake, but not sure which side. The little white plastic thing IS a retainer for the harness & there was foldable tab on the right factory valve cover to hold it in place. Someone here will have a definite answer for you. You're doing a fantastic job by the way. Just get rid of the plastic fuel filter & long rubber hoses for the fuel line. Short sections of rubber fuel line are all you want on the filter, which should be metal. Plastic & rubber is a fuel leak waiting to happen.