have a 1984 f150 4x4 with 302 engine. looks like whoever had it before put an upgraded intake manifold, 4 barrel (holley) carb, and what sounds like a cam. I say all that to ask if the stock engine had enough "beef" to support large mudder tires and play in the mud without being embarassed.
My 83 F150 4x4 with the 302 did just fine with the mudders on it and it was bone stock, but as seeing there has been a few upgrade to your truck I would say you shoud be fine, as long as you dont go crazy with it. but if you want to go "big" I would really recommend a "bigger engine" with more output. Hope this helps and best of luck.
Search Ford F-150 Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Ford F-150 Experts