Re: thornley header gasket?
You can use the stocker as long as the head is stock. The Stock gasket has square holes like the stock exhaust ports, and the Thorley gasket has round holes like the header. If you get a Thorley gasket without the instructions, they say to retighten the header after an hour, after a day, and after a week. They say the only way to destroy a Thorley gasket is to not have the header tightened down enough. I'm using the stock gasket on my 1.6.