headers/exaust for my Valiant?

I'm looking to get headers for my '70 valiant. I don't need any expensive insane ones just a lil better that stock manifolds. only problems I have so far is that I have power steering, I have to move my passenger exaust pipe down an inch to get the oil fiter off. I also wanna know what size of pipe I should get for exaust and am looking for a nice low not to loud muffler sound, any answers would be awsome