"You asked for it -- ROL did it!" In response to the demands of the aftermarket, ROL's technicians have designed, tested and perfected the world's toughest head gaskets. Beginning with a rugged steel core, a 'Grafoil' facing is added to both sides to withstand temperatures up to 2100 degrees F. The special stainless steel fire rings contain the heat and pressure within the combustion chamber for maximum power and efficiency. Then, a silicone outer coating on both sides of the 'Grafoil' provides superior cold sealing ability during start-up and warm-up. Not done yet, then a Pozi-Seal beading is applied to provide extra sealing around passages that carry oil and coolant. Want more information? Just e-mail me for links to the sales flyers from ROL. And, YES, these will work for your aluminum heads on a steel block application!