There is a factory diagram for the rad support.

But for rad support black and wheel well undercoating, I'd go off original examples. I know there was an old thread on E-body rad support backout showing examples of how deep into the headlight bucket area. There's variation.

On wheel well's I remember threads with dave walden and troy bray showing example and what they did.

I have 71 challenger fenders that are totally covered behind the bucket and inside corners.