This is my first post and I have a few questions that you guys can help me with. I am the process of having a new 5.7 Vortec Marine 320 hp carb version installed in my boat. Bolted to a Cobra outdrive. A engine oil cooler has been installed as well.
1. The shop that is doing the install states I should not use synthetic oil during the break in period. As the rings may not seat. But I know the new Corvettes come with synthetic from the factory. Is this a problem?
2. Oil recommendation from the Marine engine company is.
Ambient temp above 50F - API SAE 15-40 SM
Ambient temp below 50F - API SAE 5-30 SM
3. I ordered a case of Amsoil-4-Stroke Marine Synthetic [WCF] SAE 10W-40. I notice it is not SM rated but on the Amsoil site it shows it is ok to use in an I/O. Is this the correct oil to use?
Thanks four comments in advance.