what intake gaskets did you use ? you need to use the rect port gaskets with a o port if the intake is rect port .heads sounds like your sucking oil out of the lifter valley intake is not sealing and that could be gaskets or the intake angle is off or needs to be fitted to the engine by cutting the intake or thicker intake gaskets or maybe thinner gaskets they come in 060 and 125 as well as carbs need work hard to say what you have going on