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Thank you for trusting us with your questions. How quickly did the smoking begin? immediately? Where, exactly, did you use silicone sealant?
OK, well, that explains at least 1 problem. You should never use any sealer on a headgasket. Its not needed and could prevent proper torqueing of the head bolts. Not to mention, it likely squeezed some of that sealant into the oil jackets, water jackets, and combustion chambers. This could have some pretty serious consequences. The sealant can plug water passages, but most likely would get caught in the oil pickup screen on bottom of the engine. This can cause oil starvation with disastrous effects. Most likely, the head gaskets are either installed backwards or on the wrong side as well, as this would explain the immediate smoking. Hate to be the bearer of bad news, but your looking at some work here to remove the heads again and install new head gaskets after a thorough cleaning of the block and heads. Remember, use NO sealant of any kind on the head gaskets. I would also recommend removal of the oil pan and a good inspection and cleaning there as well,