Any engine swap will be lots of custom work. The mounts will have to be changed as well as wiring the 3 engines that were offered in these trucks in 96 don't share much in commonality so if your going to do the work might as well go 5.0 same work and will almost triple the power potential. But thats my .02 cents if it wasn't for emissions mine would already have one but I'm stuck with my 3.0 and trust me there is no cheap/easy way to beef these motors up. But if your dead set on your 4 banger check out a turbo from an svo that swap has been done and with great results.
New DD-2009 Ford Mustang GT/CS candy apple red.
(sold)2003 XLT Tan 3.0L V6 5-speed, Lots of mods.