Anyone polish an LA timing chain cover before?

I used to have a cool chrome plated one, then I found another one but it was peeling badly. Why can't I seem to be able to polish this cast AL one I have? Its completely stripped of paint, smooth as glass but it just wont take a shine. Ive use 1000 grit sandpaper, a buffing wheel, rouge/black/white compound. Im ready to take it to a polisher. Any tips? Crappy metal? I remember M/T covers were hard to polish too, inferior metal. Leanne, can you powder coat this to look chrome like?