Here I have demonstrated how to remove the three bolt flanges off the end of headers and install our Marman flanges. The reason why we do this is because with the 3 bolt flanges you can’t seem to get them to stop leaking. Plus the bolts do back out causing a blow out of the gasket by using our Marman flanges, you will no longer have any leaks. If you count the parts that are required for a 3 bolt flange connection including the flanges the gaskets and all the nuts and bolts there’s 27 pieces. When you use our Marman flange assembly, there is only 4. The male and the female ends the gasket and the clamp. Why not go V-band? Because they leak as well. These have a 1000lb burst pressure on them without leaks. V-bands have a 3-4% leak at ANY pressure.
This video shows how to repair the threads on a bolt or a piece of all thread rod.