I have a rebuilt 402 big block engine in my chevelle ss. It has approximatley 1500 miles on a complete rebuild. The heads where reworked with new seals and a going over. everything has been fine up until this point.
Just here recently the car when coming down from cruising to idle (such as a stop light)when you take off it leaves a puff of oil smoke out of passanger side pipe. cruising it is fine and aceleration is fine no smoke.
At start up there is no smoke and it doen't seem to do it when it is cold. I might Add this is a 4 speed car. I pulled plugs and there is no sign of deposits, and they look great. compression is 160 in all cylinders. All the guides and new umbrella seals where used in heads. Is it possible a valve seal is bad or a retainer ruined it? car runs excellent just started this problem. pcv valve and breather is good. There is no question this is oil smoke. any sugestions.

If I had to guess I'd say it was a piston ring problem ex: not seated, cracked. Since you have good even compression in all cylnders it's hard to say.