I had a serious blow by problem; was losing a quart of
oil every tank of gas. I did the same thing as Roscoe before I pulled the intake manifold and realized that it was leaking. My engine builder put in some thin aluminum plates to block off the carb pre-heater (a port that connected both sides of the exhaust through the manifold.). This small plate caused a leak in the gasket.
I pulled the plate and put a new gasket in, now I have 100%
oil retention. Nice!
Now if I could only fix the crack in my
oil pan and the leak in my fuel cell!