My 59 with 352 engine and original exhaust manifolds keeps developing leaks at the exhaust flange. Not at the head mating surface but at the surface where the exhaust pipes attach. New gaskets are a temporary fix and before long I begin to hear that annoying ticking sound under an engine load. My 60's Fords all use a better round donut style gasket, but this 59 had a flat gasket and it just doesn't seem to hold up. My surfaces look good but I keep developing leaks. Any ideas? What do you guys do?