I would be very careful as to saying that when Jesus `preached` to the spirits in prison that some could be saved. Notice that it says `who formerly were disobedient.`
Not a literal translation:
20 who formerly were disobedient (544 ἀπειθέω apeitheo) when once the Divine longsuffering waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight souls, were saved through water. (1 Pet. 3:20 NKJ)
544 ἀπειθέω apeitheo
Meaning: 1) not to allow one's self to be persuaded 1a) to refuse or withhold belief 1b) to refuse belief and obedience 2) not to comply with - Strong's Concordance
They formerly couldn't be convinced God would forgive their "abominable nature" (the image of God confused with the image of angels Gen. 6:2, 4), so they refused to heed Noah's preaching.
Because they were a "special case", Our LORD Jesus makes a "special trip" to the segregated prison in hell, to preach God really would forgive the sins of the angelic fathers and human mothers. These "men of renown" did nothing evil, but they just couldn't believe God would forgive the corruption of the image of God in man. Notice "corruption" is why God caused the flood:
11 The earth also was corrupt before God, and the earth was filled with violence.
12 So God looked upon the earth, and indeed it was corrupt; for all flesh had corrupted their way on the earth.
13 And God said to Noah, "The end of all flesh has come before Me, for the earth is filled with violence through them; and behold, I will destroy them with the earth. (Gen. 6:11-13 NKJ)
So they had valid reasons to not believe Noah. And because they couldn't believe, they were "disobedient". But THAT translation is misleading. A word study of 544 ἀπειθέω apeitheo confirms they were "disobedient" because they "disbelieved":
Various translations:
"He who believes in the Son has everlasting life; and he who does not believe (544 ἀπειθέω apeitheo) the Son shall not see life, but the wrath of God abides on him." (Jn. 3:36 NKJ)
who sometime disbelieved, when once the long-suffering of God did wait, in days of Noah -- an ark being preparing -- in which few, that is, eight souls, were saved through water; (1 Pet. 3:20 YLT) Young's Literal Translation
They refused to believe long ago, while God patiently waited to receive them, in Noah's time when the ark was being built. In it only a few, that is eight souls, were saved through water. (1 Pet. 3:20 NJB)
This last is hyper literal
not-persuade-do sometime when from-out-receive the the god long-passion-ance in day Noah down-implement-be ark into which few this be eight soul through-safe through water (1 Pet. 3:20 BTGNT)
BTGNT The Transformation Greek New Testament (2014)
Copyright © 2010 by Jan Hoogland
The Concept of Transformation in the Transformational Greek New Testament.
The same event can be described in English and in biblical Greek with equal accuracy. Unfortunately, it does not follow that Greek as source can be translated into English as target with equal accuracy. In fact, loss of accuracy in the translation process is a very serious matter. That is because Greek grammar differs—greatly so—from English grammar and because the two-tiered structure of word meaning prevents its accurate transfer. Consequently, any translation suffers from a serious loss of accuracy, leaving the direct reading of the Greek text—barring further study—as the only way to understand it accurately.
The obvious solution to this problem is to learn Greek. In practice, however, this is not possible because biblical Greek is no longer spoken and its acquisition and maintenance requires too much effort for most people. Study of the translated text will provide a more accurate understanding of the Greek text, but existing study tools too often reflect the shortcomings of their writers. The large variety of opinions on the meaning of the Greek text motivates the amateur to form his own understanding, which is what transformation offers in a practical manner.
While translation aims to transfer the meaning of the Greek text to the English mind, transformation aims to connect the English mind with the Greek text.
Transformation may be likened to a magic window through which we can read the Greek text without knowing Greek. It should be kept foremost in mind that a transform, by definition, is identical in content to the Greek text, no more, no less.
Transformation changes the Greek text into a form that allows the English mind to understand its grammatical features and word meanings. The process largely bypasses the need to learn Greek but its application is limited to a suitably and elaborately prepared Greek text. The method is designed for amateurs without time to learn Greek. Advanced transform readers will understand the text reasonably quickly, while beginning readers will be quite slow, but the acquired accuracy in understanding is basically the same in both cases.