Idle surge

I pulled the intake. What I found was oil on the gasket between it and the aluminum head on both sides of the engine? I redid the lifter preload. The rockers are adjustable. I did not find anything out of the ordinary.I would like to know who uses the end gaskets on the intake and who uses silicone? THe carb had been enrichened on the idle circuit. That did not seem to help. Upon reassembly I wiil swap to a second carburator just to see if it is there. I am hoping that the intake was the culpprit. The advance springs did occur to me, but I figured that since it is a new out of the box unit and the car idles 600-650, that it wasn't the cause. I will check for that with my timing light. Thank you for all the replies.