You sure hit the nail on the head with that one Jim, I too have had numerous problems with headers. Here are some of the things I have done to solve some of them.
-Leaks, after finally having enough of header exhaust flange leaks on my 69 Mustang (the drivers side was an absolute nightmare to replace) I finally removed them and cut off the flange and fabricated some 5/8" thick ones using the originals as templates, this completely solved the leaks and I then went to a reusable copper gasket. Funny thing happened as a side effect the bolts no longer loosened up with normal use?!
-Low ground clearance, After dragging around those headers for one winter and freezing the carb and air filter from the steam more than once I put on a skid plate, not pretty but it saved them from certain destruction. There was just no room for a full length header on this car and having them under the car was not ideal. After I had seen a friends Dodge Dart with fender well headers, I now think this is the ideal solution, to bad not many MFG's make them.
-Noise, At first the sound of headers under the hood was a novelty but after a while it became an annoyance, the under hood heat was a major problem as well. The belts and hoses seemed to need replacing regularily from the heat bake. Those header blankets seem like a good idea although I have not used one before, the wrap type over insulate the steel and the carbon in the steel is consumed leading to brittle fracture from decarbonization. The stainless steel versions are better in this regard but still not immune. I have heard nothing but great reviews from people who had their headers Jet Hot coated and if I buy another set of quality headers they will get this treatment after the flange modification.
I now consider a set of headers an unfinished product that requires finishing before I am satisfied with them, I wish you luck with your next set.
“She may not look like much, but she's got it where it counts, kid. I've made a lot of special modifications myself.”
— Han Solo