I had an issue blowing gaskets out on one side that I just couldn't seem to cure. I tried copper gaskets and those didn't help. Then heard about remflex gaskets and they completely cured the problem. Best I've ever used - by far. They are able to compress quite a bit yet retain some "spring" so they keep the seal. If you check out their site you'll see why they are likely to solve the problem you have. Another nice thing is that they are a family-owned business and are small enough to make whatever you need. So if you were to have a special port configuration of some sort they can custom make a set. Call them and tell them what heads you have as they may have created a set special for those that's not listed in their catalog.
www.remflex.com
Oh, also I sent them a collector 4 into 4 gasket and they made a template for those as well. That was for a FFR header to sidepipe but I think they pretty much fit all of them.