Sierra 18-2556 Mercruiser Drive Shaft Housing to Bell Housing GasketSierra high-quality engine parts are designed to meet OEM specifications. Fits IA/IB/IC & EZ Shift (1964-1966); Interchangeable with: Mercruiser Stern Drive; 27-35996A1; 27-35996; Application:Mercruiser Stern Drive Model: IA/IB/IC; 1964-1965; s/n 1684188 thru 1777798; Model: IA/IB/IC EZ-SHIFT; 1965-1966; s/n 1776349 thru 2065189;