My c7 with tsp 1 7/8th headers, 3”xpipe, afe air intake and ported intake/throttle body untuned vs my c5z with tsp 1 3/4 headers welded to stock h pipe, 2 runs with me driving c5z 2 runs with me driving c7, not sure why the difference the other driver drives very good, maybe driver weight about ~60 lbs.