Y Block Question

[GAR64]

I have a 56 with a 292 that sat for about 15 years. Has original 4bbl. Siphoned out as much gas as I could, added fresh with some seafoam and it is running pretty good. Smokes pretty good though. Some say I probably need to rebuild (rings) others say valve seals and another thought maybe clogged oil passages on top could cause it to smoke. Any thoughts from you guys would be appreciated. Having fun with this car...