B.A.M aka "Black Azz Mike
Oh yeah! The drain holes are as small as a pinky finger and have no love on returning the oil fast enuff. I do think that the edelbrocks compensated to help with this problem. I know that mondello's heads are full worked and come with holes already drilled and tapped for external lines.i never realized there was that much oil backed up in the heads.
On another note, you can make oil restricted pushrods with pipecleaners from wall-mart for about $5. Twist 2 of them together and insert them into the pushrods. THen cut them .250 inches shorter than the pushrods on both ends. THis is the old skool way of restricting the top end and its proven to work