http://en.wikipedia.org/wiki/List_of_GM_engines Scroll down to "Flat-6". Also, click on Flat-6 to get: http://en.wikipedia.org/wiki/Flat-6 Also click on "A brief history of the Corvair" to get: http://www.corvair.org/vairhistory.php Bruce W. Schug President, CORSA South Carolina Greenville, SC bwschug at charter.net CORSA member since 1980 '67 Monza. "67AC140"