A lot of IHRA crate motor small blocks, including myself, run the TTI stepped 1 5/8" -1 3/4" headers with good results in Stock. Heard some NHRA racers also do but can't confirm. Mine were coated inside & out. Not sure how the would be in SS, but TTI does have a 1 7/8" straight version.
http://www.ttiexhaust.com/