496magho in a 272 Baja??
 

Gentlemen,
I am repowering to a 2003 496 MAG HO in a 1996 272 Baja. The engine has 12 hours on it. What kind of oil should I use? One suggestion I had was synthetic 30 or 40 weight as opposed to the Mercruiser oil???? Any suggestions?? Will I have problems with the rings sealing with the synthetic oil?
thanks!

I have heard several theories about breaking a motor in with mineral based oil as opposed to breaking in with synthetic. Supposedly the rings won't seat properly if you try and break in with synthetic. A stock motor/bore/rings should be pretty much seated on initial startup according to GM and you have 12 hours on the motor. I have used Mobil One Synthetic 10-40 after the first twenty hours and I pulled the heads after 40 hours and everything looks rosey. My sbc motor made optimum oil pressure with 40 weight mineral or 10-40 synthetic. 30 weight or synthetic 10-30 didn't make enough oil pressure at idle for my motor. Synthetic oil should give you a few more horses and it will extend ring life.

thanks...I was thinking mobil one 10-40 as well.