In 68, it was galvanized finish and bolted to the exhaust manifold using 2 exhaust manifold bolts. The tube bolted to the heat stove using one small sheet metal screw. I just finish de-rusting mine and it cleaned up very nice with a light wire wheel and scotchbrite pad. I then used a VHT Flameproof high temp clear which gave it a nice sheen and cured the paint using a heat gun. Hopefully this will prevent rust from coming back.