If they are paper or fiber, then a razor blade will do it, or bolt em to your headers and use something like a dremel or rot-zip with the cutting bits (the spiral ones).
If your gaskets are not big enough, make sure your headers are big enough....may need to get a high speed grinder and taper the openings a little in the headers as well...
Toma
If your gaskets are not big enough, make sure your headers are big enough....may need to get a high speed grinder and taper the openings a little in the headers as well...
Toma