Small block headers: worst to best fitting. List your experience.
I would say that Doug's 453 might be the best small block headers for a bodies on the market. They hug the block (I believe they require mini-starter) and I think they work with both power steering boxes. Other than that, most other sets I have seen from cheap to expensive have either the #1 or #3 exhaust pipe going up and over the other cylinders and then back down next to #7. I'm not a huge fan of this design because it gets in the way of the spark plugs. Another thing to note is that most "wrap" around the steering linkage under the car meaning the center link needs to come out if you ever want to swap headers. This also causes them to hang low under the car.
My car came with no-name headers and I know what I don't like about them (listed) and when they bite the dust I made up my mind years ago that I will replace them with the Doug's headers personally
P.S. I saw these on an a body at a car show and I grabbed some pics because I was so impressed at how they fit