I use scrubbing bubbles, and a little elbow grease nice and shiny every time. as for the header take it off and take it to a buffing wheel

 

I like that Quick-n-Brite stuff in the tub. It looks like pink thick vaseline, but it cuts grease nicely. It is non-toxic as well. I grab some and rub it into the wash mit, and then start scrubbing the engine, etc. As far as the header, I don't know. Those headers are a bad combination of heat and dirt. Almost like making bricks in a kiln.