Item is 100% New, Never used or installed. has NO O2 Sensor locations. Header features 8-2 light weight design. 1.6" Inlet and 2.5" Outlet Designed to fit the Chevrolet Small Block 262, 265, 267, 283, 302, 305, 307, 327, 350 & 400 V8 Engine. Hugs the block for a closer fit and extra clearance CNC machine flanges with TIG and MIG welded construction 3 Stage polish finish. Product does not come with installation instructions, please refer to a shop/factory manual for installation.