Fel Pro makes intake gaskets for many bolt arrangements and port sizes for the SBChevy head that come usually in .060 inch or .120 inch thicknesses. Sometimes you can find choices in .030/.035 and .040/.045. You have to also check for the head angle, production is 23 degrees but there over the counter GMPP and aftermarket heads at 18 and 15 degrees so you have to watch this as well when ordering.First time on this forum but I was wondering if anyone is running procomp heads with a professional products crosswinds manifold. I have heard that you need to run a thicker gasket to help runner alinement. Is this true ? thanks for any input.