Cast iron exhaust manifolds weld fine, anybody who can arc weld can do it, they're Malleable iron, engine blocks and intakes are gray iron and are a problem to weld, preheat, short welds, peening 'til cool, etc.. I've even seen exhaust manifolds welded with regular steel rods and worked fine- the recommended rod for malleable iron stuff is a nickle rod--some people dont appreciate cheap--how do you make a "split manifold" with out welding?
