THIS IS A TOP END GASKET SET FOR ALL CT90'S ATC90'S,AND(ATC110'S 79 AND 80) BUT!!!!!!IF YOU HAVE A (CT90K0 THRU K4) OR A ATC90 WITH A ENGINE SERIAL NUMBER LESS THAN 1113934 THE HEAD GASKET IN THIS KIT WON'T WORK,IF YOU WANT A NEW HEAD GASKET, YOU WILL HAVE TO BUY THE ONE NEXT TO THIS ITEM. OUR NUMBER HDGAS90,,SORRY AND THANKS TOP END GASKET SET 90CC ALL BUT SEE DISC. ATC110_79&80 (GTE522) GTE522$11.99 *HEAD GASKET CT90 K0toK4 ATC90 EARLY (77R) THIS IS THE ALL ROUND HEAD GASKET THAT THE CT90K0 THRU K4 TOOK AND THE EARLY ATC90'S THE NEWER CT'S AND ATC'S HAVE THREE NOTCHES IN THE HEAD GASKETS. THE ALL ROUND HEAD GASKET WORKS FOR (CT90K0 THRU K4) OR AN ATC90 WITH A ENGINE SERIAL NUMBER SMALLER THAN 1113934 77R$5.99