headers
For underchassis headers you have 2 1/2 choices. TTI, Dougs and Spitfire. TTI are ridiculously expensive, very well made and may require a really expensive starter. Dougs are ridiculously expensive, well made and may not require a special starter. Neither of these work well with power steering, and 4 speed linkage is a hassle. Spitfires are made by a shadetree guy named Harold. He makes a batch when he makes a batch, ships them every now and then, so you headers are some priority behind his day job and whatever else he is doing. Pre-pay with caution.
Good luck, let us know how it turns out.