To those of you who opt for SLP headers DO NOT USE their gaskets on either the head flange or donut at the collector. I've lived with these sorry cheap gaskets for two years simply because I did not have the time to replace them. I can't believe SLP ships this junk with their headers. I used FelPro on the head flange. I found sintered iron donuts for the collectors for a 1978 Chev P/U with a 350. I've had the FelPros on my truck for 6 years with nary a tick so they should be OK.