You can run a trac loc if you want but you will have to take off the ring gear to install it. If you know how to set up gears go for it. I used to run one years ago and seemed to do OK but I'd still have only one tire spin up front but that could be do to the 38's I run. When I upgraded to the Detroit it was a huge difference in traction. So if I were you, get a Detroit up front and be done with it. No need to be unhappy with a cheap posi and have only a slight increase in traction than now.
Its your choice...