I have a set of Downey headers on my 1993 Toyota 4runner with the 3 liter V6 engine. The exhaust manifold gasket has started to leak so I would like to replace it. I called the store where I bought the header a few years ago and they tell me Downey is out of business. I understand the factory exhaust manifold gaskets won't work with these headers. Can anyone suggest where I can get a new gasket or any way to fix the leak?

The gasket has eroded in one spot at one exhaust port and makes a ticking noise when I accelerate. It doesn't seem to have any effect on how the car runs, but the noise is irritating and I can't pass the annual safety inspection. I have tried tightening the bolts on the headers.