For $3,900, I wouldn't even bother with a 4.0L.  For that much coin you could move to a 4.3L or even a 5.3L.  Means more work and not just one weekend.  But then you won't be wanting more with a 4.0L...  It doesn't make sense to swap in a 4.0L and stroke it or supercharge it when you could have a V8 and be done.  With that much money, you could easily move into 6.0L range.