These are the custom headers that were welded up by Mark Erney and used in the dyno testing. They are almost equal-length units that feature a 2.00-inch primary diameter, 34-inch long primary tubes, and a 3 1/2-inch collector. Why not equal length? Jim explains, "They were as close as we could get. The problem with Pontiacs and round ports is the huge crossmember under the engine. So to avoid a 90-degree turn, we had to position the number 1 and 2 primaries in front of the crossmember and then turn them under the car to fit the early GTOs. They still worked very well."