[VinnyC]

This engine was recently rebuilt with used pistons and cyls. that were supposedly within spec. New rings were used. Once put back together and fired up - the engine smokes on idle but much worse when the throttle is applied. Its a crazy amount of smoke...enough to fill the garage.
Initially, I assumed that the rings had not seated and the smoke would disappear eventually - but that has not happened yet. I'm not driving it since the rebuild because of this.

Now i've noticed that black nasty oil spits out from the tailpipe and pools up in the tailpipe area...

Could someone please give me some ideas as to why this might be happening?
If the rings were not seated would that much oil be burned and sent out the tailpipe? Is it possible that the heads could have a bad or leaky valve in addition to the ring issue? Any help or ideas would be greatly appreciated.