Michigan Motorz carries virtually every marine flywheel ever used in marine applications. There are only two flywheel sizes used in GM based marine engines: a 12¾" and a 14" flywheel (true inboard flywheels are always 14" with the ring gear on the outside edge of the flywheel). The crank bolt pattern of each engine (where the flywheel mates on the back crankshaft), is different for each engine. Simply said, a 14" flywheel from a 4.3L engine will not fit or bolt on a 5.7L engine, even though they are both 14" in diameter.
When ordering a flywheel, first measure your flywheel diameter (most are 14"), identify the YEAR of the engine, then identify your exact engine (3.0L, 4.3L, 5.7L, etc).
If you have any questions, please call us for assistance at: (248) 524-9600.