BASE MARINE ENGINES GM 3.0L INLINE 4 CYLINDER 145 Horsepower Marine Engine 181 CID Displacement 3.0L (181 cid) Cylinders L-4 Propshaft HP 145 Operating RPM 4300-4600 Bore 4.00 in. Stroke 3.60 in. Compression 9.25:1 Engine Rotation Left Hand Only   Product information and specifications are subject to change without notice. GM MARINE ENGINES • A high-flow cylinder head with straighter intake ports and a higher compression ratio delivers significantly more horsepower. • Cylinder heads feature exhaust valve seat inserts for improved durability. • Nodular iron crankshaft for increased strength and durability. • Camshaft is specifically designed for marine duty cycles and optimized for maximum performance. • High-silicon cast aluminum pistons for improved durability. • Cylinder heads have exhaust valve seat inserts for improved durability. • Cylinder case has brass water jacket core support plugs for resistance to corrosion. • 14" diameter flywheel provides common size with other GM engines. • Common rear face on all GM marine engines for easy hook-up with housing. • The compact packaging of the 3.0L L4 gasoline engine allows for excellent fuel economy with an impressive power-to-weight ratio.