Motor smokes

[exrodder]

My car has been on the road for the past month and I have 50o miles on it. It doesn't smoke on start up or running down the road that is noticable but when I stop at a red light or stop sign and sit and let it idle, smoke comes out the pipes. It doesn't smoke from the same side every time, one time left, one time right. I took valve covers off to see if oil returns were blocked and they seem clear. The engine is 390 with restricters under the rocker stand as I was told to do. Local machine shop did head work and said that the guides were ok but now I wonder. Any ideas. I was told that maybe oil is getting sucked in around bottom of intake gasket, but car idles fine. The oil is evident on plugs 1 & 6 with 1 being the worst. Ran the hell out of motor after machine shop said moter"probably" didn't have enough miles on it. Have built other motors and no problem. After running car in 2nd gear from 3500 to 5000 for 5 miles, came to stop sign, stopped, took off with no smoke. But, stopped, idles for around 20 seconds and it started to smoke out left side more than right. Next time I ran car, smokes out right morte than left. What gives. Help!!! Realloy embarrasing !!!!

exrodder