Have this new motor 489 stroker maybe 4 hrs on it now and from day 1, oil turns black within 1/2 hour run time, and the back outside of the boat has a black film on it, and has a lot of blow by smoke coming out of the valve cover breathers, is all this related and why. BBC 489 650 H.P.
Thanks in Advance.
Sounds like the rings are allowing a lot of by-pass for whatever reasons, such as they never seated or are installed wrong, etc.
Also sounds like it is running very rich....the plugs should tell the tale...
New pistons and rings? Bores deglazed, etc?