I have a 1996 Ford F-150 4x4 with the 4.9L I-6 mated to a 5-speed.  I am looking for additions that will help bring up the power some.  Also any Ideas on how big of tires i can go with out a lift. Any help would be helpful.  Thank you  

A couple a things here. First that year and model truck is usually handicapped by axle ratios. They tended to gear them tall to try to squeak out that last fraction of MPG  on EPA MPG test for fleet averages. Chevy did it too with some models and the result was trucks that felt pretty anemic at times. Also MPG in real world usually was not as good as it could be because demands of EPA test then did not reflect real world demands or conditions. Deeper axle gears would give you a noticeable boost in usable power most than any engine tweak by far. Also if you plan bigger tires they will make matters worst if you do not regear. The 4.9 is not a bad motor, it just needs help in the form of deeper gear. Another thing, that TTB front axle does not lend itself it easy lifts nor is it very friendly to tires (accelerated tire wear)and handling when you do it because of its swing axle design.I would suggest a minimal increase in tire size to maybe 31's or so as these are not good trucks to lift and a better left near stock if longer service life, better tire life and handling is desired.