Yeah I'm looking into hedman step tubed headers. From 1-3/4" to 1-7/8" to a 3" or 3-1/2" collectors. Equal length primaries. I've done the research on my heads, cam and valve sizes. With my flow I came to 1-3/4" primary size. With the blower I'm at 123-125% volumetric efficiency. The ones they list for these trucks are the same as the hooker comps I am using now. Which led me to post this thread about car headers that are compatible. My motor is far from stock. My current headers are 1-5/8" tubes to a 2.5" collector. Pretty lame to go from 2.5" collector to 3" exhaust. My exhaust is dual 3" with an H pipe right after the trans crossmember. The exhaust dumps before the rear axle after single chamber flow (noise) master mufflers.