I know that this is has probably been discussed many times before, so forgive me for asking one more time. I have a ticking sound coming from the passenger side of the engine that is present only at idle speed. When I accelerate the sound seems to go away. I have felt all around the header and still can't seem to find the leak ( I have the burns to prove it). I read in another post that a faulty spark plug wire was the to blame on a few engines, but wouldn't the ticking noise still be present at high RPM? I hate the thought of changing that header gasket, because it is on the side of the A/C.

Look for black soot around all your gaskets at the header flange and at collector too.
Also you can use a piece of vacuum hose as a stethoscope to listen and not get burns.;)

a