Possible 2.9 to 4.0 swap need advice

[jkufen]

I have a 86 B2 4x4 2.9L and my dad has a 1990 Ford Ranger 2x4 4.0L. We both want to rebuild our motors because there are a lot of miles on both and I was thinking does anyone know if there is a significant performance change to where its worth swapping engines? If its not going to benefit me much its not worth the work, but from what I have read it such just be a bolt up swap right? Thanks!