Jet boat engine question?

Question

I have a 69 396 chevy jet boat engine. On one side the breather has tons of oil blow by. Does worse the more rpms I push. I have changed the gaskets because they were old, and also put baffled valve covers and breathers on both sides. whats wrong what should I do.

Answer 1

Sounds like you have bad valve seals, this can be confirmed by a leakdown test. Escaping gasses are pressurizing the valve cover chamber, causing the blow-by.  Time to have the heads rebuilt.