RC Helicopter 60 Size Side Exhaust Engine Header. This header has been previously mounted and flown. The header has been repaired by Tig welding near the header and exhaust flange. Please see the photos for the details on this item. If you have any questions, please send me a message. Note flange hole spacing is 42mm center to center. Flange mounting holes are .130 inches. Flange dimensions are: 50mm long and 15mm wide.