Oh and one more thing, make sure you know EXACTLY what your engine is and what year. You can find the engine code on the rear of your engine, drivers side below the cylinder head there is a flat casting. the number is there probably hiding under some grease. Once you get the number go here to find out all you need to know about your engine so you don't get the wrong gasket.
http://www.nastyz28.com/sbchevy/sblock.html