There are too many variables to answer that question. 5.0 or 4cyl. Spline count on the new posi unit since our cars arent factory posi. Do you want to change over to disk brakes or keep drums? And the gear ratio has nothing to do with a 5 lug conversion.
Without trying to offend you, it sounds like you're going to spend a lot of money to pay someone else to do this job for you. Or, your going to need another car to drive because you've never really worked on one before and it's going to take more than the few hours it should.
Go to the tech section and check the sticky's. If you understand cars, and know what you already have, there should be more than enough answers there to your question.