john a,
This is one of the few places that I think the New International Version is helpful.
For this reason the gospel was preached even to those who are now dead, so that they might be judged according to men in regard to the body, but live according to God in regard to the Spirit. 1 Peter 4:6
Calvin comments in the same way only a bit more complexly:
"For this cause was the gospel preached also to them that are dead, or, He has been evangelized to the dead. We see in what sense he takes the former passage in the third chapter, even that death does not hinder Christ from being always our defender.
...the meaning is almost the same, that is, that Christ had been made known as a redeemer to the dead, or that salvation had been made known to them by the gospel. But if the grace of Christ once penetrated to the dead, there is no doubt but that we shall partake of it when dead. We then set for it limits much too narrow, if we confine it to the present life."
This verse should not be taken as a literal "preaching to the dead" but as a preaching to those
when they were alive but are now dead.
Denny
Romans 3:22-24