Have you checked into New Jersey's auto emissions rules?
What is require to legally install a different engine and have it pass and receive its emission's certification?
Converting to a V8 is a very expensive, time consuming project, with all the electronic and emissions problems to figure out.
Stroking your existing 4.0 can provide 300-HP and a bunch torque, with a little planning. Installing it is a weekend job, since it's a direct bolt-in engine.
It is so simple compared to a conversion and will get you to the same place, unless you want a stupid amount of power.
With a well built engine, it will pass the smog test and, if left stock looking, will not catch the attention of the inspector. Good luck having the same with the V8.