Didn't have to monkey anything on mine- went from a '79 6cyl. 7.5" to an '89 5.0 8.8" with no problems; no compression fittings, no unions. They were very different, but it all still bolted right up and worked. Same deal going from my '84 5.0 7.5" to a '90 5.0 8.8"- just took using the right parts from each. If you have complete lines now, you should have everything you need.
Oh- and yes, the driveshafts are the same.