Mercruiser (Parts)Mercruiser part #76850A2, Couplers Chevy Engine Couplers, SUPER DISCOUNT 850 COUPLER, DIISCOUNT ENGINE DRIVE COUPLER, ENGINE RUBBER COUPLER DISCOUNT COUPLER, Couplers MERCRUISER ENGINE COUPLER CHEVROLET ENGINE COUPLER 850 ENGINE COUPLER DISCOUNT MERCRUISER ENGINE COUPLER TRIANGLE ENGINE COUPLER REAR ENGINE DRIVE COUPLER MERCRUISER COUPLER WITH SHAFT, REAR ENGINE COUPLER MERCRUISER, 505 ENGINE CONVERSION COUPLER, FORD STYLE ENGINE COUPLER MERCRUISER. 8-2175 Engine Coupler Kit 18-2175 Replaces Mercruiser part #18643A7. comes with new style12-1/2 inch yoke shaft;. Flex plate style for late style 12-1/2 inch Flywheel bolt pattern. GM (Chevy) 4.3. 5.0 and 5.7-liter engines with 14 inch flywheels. (also some early 7.4-Liter engine using Alpha outdrive).(Note:if you have newer yoke, see part #18-2323 w/o yoke). 18-2171 Engine Coupler 18-2171 Replaces Mercruiser part #76850A2. For all early GM Engines that had 3-1/2 inch; crank shaft bolt pattern, 12-1/2 inch flywheel. Early GM (Chevy) 4,6 and 8 -cylinder engines.(engines with 2-piece rear main seals). Do not use if you have a MR/Alpha/Bravo with 12 inch;Triangular inch 3 bolt coupler. 18-2172 Engine Coupler Kit 18-2172 Replaces Mercruiser part #14505A2. Use when you are replaceing older, Chevy(GM V-6 and V-8 engines), with 2-piece rear main seal engine (which had a 3-1/2 inch; crankshaft bolt pattern) with a newer 1-piece rear main seal engine that has the smaller 3 inch; crankshaft bolt pattern. Comes with studs, washers and nuts. 18-2173 Engine Coupler (FORD Engines)18-2173 Replaces Mercruiser part #59826A3. For Ford Engines. Bolts to crankshaft bolts. 18-2414 Engine Coupler (Late 470's Engines) 18-2414 Fits Mercruiser 3.7-Liter, 4-cylinder inch;aluminum blockinch; engines (1983-1989), Replaces Mercruiser # 97432A2. For 165, 170, 470 (s/n 6170297 and up) - AfterMarket Discount Marine 1-800-349-2628