replaced valve stem oil seals ... Still smoking ! 273 HP

The engine shown in the picture is NOT a sludge bomb. In fact it looks pretty clean for an engine that started out it's life with leaded gas. I'd say it has a pretty good coat of varnish, but not heavy sludge (would look like a coal bin). The Seafoam in the oil WILL soften the varnish, especially if you let the engine warm and cool a few times. Actually that engine looks good enough that I would skip the 10w30 flush oil and go straight to Rotella T6 (5w40) and just run that long term. The diesel spec oils will clean the engine and keep the carbon and such in suspension. Your best bet is to keep fresh oil in it and just drive it. The rings will release, it'll just take hot oil and time.