If one wanted to change the header panel from the early 2 headlights to the late 4 headlights, does the core support need to be changed as well? Do the 82 up core supports have 2 or 4 recesses for the buckets to sit in? What about the wiring harness?

would like to know too, 4 makes it look cooler but if it takes alot of work then im out.

I imagine as with the aluminum core support the opening for the dual headlight buckets can be cut larger.

I'd like to have one of those aluminum supports before I go back together with it.

Yes they are different as is the wiring and fenders. As mentioned I guess you might could cut or butcher it and make it work but I personally do not do things that way myself. The picture in my avatar is a 79 and was converted over to the 82 up front end as you can see. Replaced the fenders so the side marker lights would be correct, replaced the radiator support along with a wiring harness for the 4 headlights. When you look under the hood of the 79 at the wiring and support you can't tell the difference from the 86 we have. Theirs defiantly some work involved but just depends on the type job you want in the end.