we have an 87 prelude si that was my wife's first new car, she plans on keeping it forever, (250k one-owner miles). The engine runs OK, but it's starting to get tired. I've tried to find info on what engines might not be a complete pain to swap in once this one finally gives out. I'm guessing the B20 might not be too bad, but I can't find info on anything prior to the 89's.

Suggestions?