[My427stang]

Well, here's my opinion, take it for what you paid LOL

If you cant seal it with a tight bolt and a good gasket, you'll have to fix the sealing surfaces.

Permatex or any other sealant IMO isnt going to last if the gasket crush is insufficient.

If it were me, on the exhaust side especially, I'd focus on lubing the threads and the hot retorque trick I said and ignore the goop. If after that (or maybe even at disassembly this time), you arent seeing a uniform gasket compression, you need to fix the real problem

However, a good gasket with a very focused even tightening, with lubed threads, can make a world of difference. Keep in mind, tightening headers can be a pain, I keep about 6-8 different wrenches I have aquired over the years with very small box ends. Some work on some cars, some work on others, but usually a combination of all gets every car.

Another good rule of thumb, "If you are tightening a header bolt with an open end wrench, its probably not tight" If that is the case, clearance or dimple the header nicely so you can get some sort of box on it. All 8 tightened evenly with a variety of box end wrenches susually is the answer to all problems

Now with exhaust manifolds its a little different story than headers, RTV can actually act as a but of a lube between two machined surfaces and let them settle together. (no gaskets at all)

However, even those, if not flat wont seal, regardless of the amount of goo you slather on them

One unrelated question, what do you do for a living? AF here, saw the live-fire signature.