I wouled only go with a 4r Trans if the truck is an all out drag or pulling truck. It's not cheap to put a 4r in a 6.0 and when u tune the truck you have to tune the engine and Trans separate. Imo for what your doing just put a really good built 5r Trans in it. That's what I did when I built my truck and I couldn't be more happier with it. Mines got the billet parts in it and a competition shift kit it in and real good converter and a 2400 stall in it. I don't know actually each and every part in it off the top of my head. It does very well on the street with the set up I have in the truck.