Ceramic Coated With A Thermal Barrier. 2-1/8 Raised-deck Step Headers. Designed for: 62-74 B-body and 70-74 E-body With Big Block With Indy Heads. Primary tube size: 2″ O.D. Secondary tube size: 2-1/8″.Collector Size: 3.5″ With 3-bolt flange. Flanges: 3/8″ thick, laser-cut, contoured for a leak free fit. For more details visit the TTI Website.Price does not include shipping. FOB from Corona, CA 92880-1726 . Shipping can be very expensive depending on your location. For an accurate shipping rate please call us.