I am polishing an intake manifold and throttle body right now and I bought these from eBay...
You could give them a try, they come in packs of 25 I think and they are 1.5 inch in diameter, very flexible and the shaft is designed to be used with a Dremel. I find them very useful for tight spots and you can use them with greaseless, emery, tripoli compounds.
Good luck!!!