the wheels are to big?
 

My father in law is letting me use his late sons truck (95 f150, 5.0 4x4 5spd manual tranny) because my truck is not 4 wheel (I have a 94f150 4.9l 4x2), and i needed something for snow since the mrs. started working. Issue, he lifted it 6 inches with a rough country lift, and put some big ol tires on it. The thing is a dog on hills, and gets ****e gas milage, and i live in a hilly area. What can i do to help with power (or maybe gas mileage?!) if anything? Maybe i should gank is 4x4 parts and throw them on my truck and ask forgiveness later haha

The MPG might be better than you think. Click this, read the caption, & then check the conversion constant:

https://www.supermotors.net/getfile/...ster-front.jpg
(phone app link)

The only things that will change the torque at the wheels are:
1) downshifting;
2) putting the t-case in 4L (effectively downshifting);
3) putting smaller tires on it ($$);
4) changing the axles' gears to a lower (numerically higher) ratio ($$$$);
5) increasing the engine's torque ($$$$$$$$)

But you're not getting much benefit from 4WD on icy pavement. You'd probably be better-off putting chains on your 2WD front & rear. There are plastic zip-tie snow "chains" that are easy & disposable, and much cheaper than steel, if you want to test it out.