so im running 1.6l, auto, 31s, 5:12s, 5 inch lift, i am looking to put in a chev 4.3l /auto/t-case and bought some 35x12x15 to put on, my trouble is it sucks now with 31s and 1.6 so im trying to figure out what to do for diffs/gears to run the 35s with the chev driveline, over twice the hp will help but i do lots of rock crawlin so i want the low end, i am thinking either yota diffs, jeep 30-35 or sammy front and leave kick rear in place, any help would be great, thanks

That is a big heavy motor to stuff in there, but it should fit.  As long as you have an automatic you should be able to crawl without issues, just make sure you have a transmission cooler.

Toyota or a 44 or 9" combo.  I would skip a 30/35 combo with 35" tires unless your getting them on the cheap.  Even with just the 30 front end you will probably need to rebuild it.

Have you looked at doing a Grand Vitara v6 swap with Toyota axles?

i can get the 4.3/auto/t case harness, computer for $600.00 i have a set of 30-35 jeep diffs, buddy has a yota less engine i can have for $450.00 so not sure witch way to go, would the grand vitara v6 bolt to my auto zuk trans, then i could do a 4:24-1 trans gear set?? with different diffs.

i can get the 4.3/auto/t case harness, computer for $600.00 i have a set of 30-35 jeep diffs, buddy has a yota less engine i can have for $450.00 so not sure witch way to go, would the grand vitara v6 bolt to my auto zuk trans, then i could do a 4:24-1 trans gear set?? with different diffs.

I do not think the GV will bolt to your 3 speed auto, but you can get a 4 speed auto or even a 5 speed auto.  But you will be hard pressed to get one for $600.  The 4.3 with its cast iron block weighs much more than the aluminum block GV, and likes lower RPS'S, so your auto gears and big tires may be in order.
Make sure you have complete wiring and a running motor, or you will be chasing gremlins for some time. 

You can swap most anything in there, making it work reliably is much harder.

i hear you about the gremlins, thats why i am trying to get all the ducks in line before i start to chop up my perfect kick lol. i have a line on a gv v6/auto/case that i will be looking in to to see what would be the better way to go, you have a good point about cast vs alum block, i like the nimbleness of the light weight kick i have now and dont want to go backwards in this project.

You should be able to bolt your stock t-case to the GV automatic, that way you can put 4:1 gears in it if you want.  As for picking up the engine/transmission/transfercase, make sure you get a vehicle with it.  With BRD HNTR's conversion we have run into a few issues with not having the proper computers for the swap, or not enough of them.

well i think i am gonna go with the 4.3/auto/case, my kid has a 30 frt(to bad low pinion) with vac disconnect(would switch to cable shift with spool) and a 8.8 (spooled) with disc brakes and full set of yj leafs and shackles i can get for 4-500, im thinkin this is the most affordable way to go, what do you think?? 

Go for it.  I think your making it a bit heavy with all of that, but it will be an interesting project. 

i read a forum on i believe was your dads build?? he did a ifs mod diff in the frt, was wondering why he stayed with the ifs and didnt just sas his unit, i am resisting the heavier components but i want the 35s and and am thinking the sas and 4.3 for power is the best solution, having the power in the little kick would be a hoot as well, i just find when we are out rock crawlin i have jack _ _ _ _ for flex and my kids cherokee just stretches its legs and keeps the tires on the ground, plus my 31s are a bit small so i figured this would be the way to go. will try to keep track of photos and try to figure out how to upload as the build progresses, thanks for the input!!

He likes the ride of the IFS front and outside of rock crawling there isn't much of an advantage to doing an SAS swap.  It's just easier to swap in a heavy duty front axle instead of making sure that the IFS works, which is why most people perform the change.