Your next task is to find out why the engine failed. Marinized engines rarely wear out, especially during the first 10 years of operation. Usually it's problems with components or poor maintenance that cause engine failure, not wear and tear. Unless the cause of the failure is determined, you may be wasting your money-especially if you're buying the block and intend to use the same alternator, starter, pumps, wiring harness, and so on. Each component should be tested before reuse. If your boat is an I/O, you may want to consider a new outdrive or, at the very least, having your existing outdrive rebuilt. There could also be problems associated with the airflow in the engine compartment. Or you may need to check out the drive train, including running gear and alignment.