As JSM said, the rub here will be finding a matching set of gears for the front. While they don't have to be an *exact* match they DO need to be pretty damn close. I've run 4.10's in the rear & 4.11's up front with no problems but that's about as far as you can step out of line without breaking something. Now of course there are exceptions to most rules and there's one here as well. In places like New England and other areas where you'd be driving in 4WD on dry pavement from time to time & this sort of driving demands identical front & rear gearing. Down here however the whole 4wd thing is pretty much just for recreational use. If you absolutely limit the use of 4wd to dirt, mud & off road situations you can get away with mismatched gears because the tires will be able to slip. On dry pavement there's just too much traction and the torque will build up in the U-joints, driveshafts & transfer case until something breaks, in the mud your tires can slip and release the built-up torque. Competition trucks will sometimes do this intentionally running a "faster" gear in the front axle to help pull & steer the truck down the track. If you were careful to only run 4WD off-road then you could install the orphan gears in the 8.8" and drive it that way until you got the $$$ to do the front. Not that I'd *recommend* doing this, simply saying that it can & has been done. Better yet would be to simply snag the gears (the axle itself is too narrow to be of any use to you, same goes for the shafts) and hold onto them until you can find a matching set for the front.
Depending on what ratio they are it could be a good deal, especially since you're looking at moving up to 35's. 4.10 would really be the better ratio for that size tire but something like a 3.90 would be pretty close & better than the stock 3.50's
