Been suitable for 34/40/44 and 50 HP engine of 1200-1600 ccm inclusive. Mexico beetle… NOT FOR BUS ENGINES WITH 1,7-2 LITRES and 24.5 + 30 HP engine suitably…. To adjust aluminum with screws… with thread around the exact tension. These pipes can insert you without the cylinder head to dismantle… to please to consider you that the screwable end to the cylinder head are installed…. Quotation per piece without seals