We used a set of Hooker 17/8-inch A-Body headers for the dyno pull because that is what we had available. We also spoke to Matt Held at Holley and he recommended using the smaller 13/4-inch Hooker header on the street for a little more low-end torque. Held doubted we'd see much of a difference at the top of the power curve with the slightly smaller tube. We used an oil filter from a 2.4L '90 Toyota pickup to clear the dyno headers. Blasphemy!