Sierra Marine 18-2172 Engine Coupler

Sierra 18-2172 Mercruiser Engine Coupler Kit. Replaces Mercruiser part # 14505A2. Use ONLY when you are replacing older GM Chevy engine that had a 2-piece rear main seal V-6 and V-8 engines and had a 3-1/2" crankshaft bolt pattern with a newer 1-piece rear main seal chevy engine that has the smaller 3" crankshaft bolt pattern. The coupler kit includes studs, washers and nuts.