I am building a jeep from nothing right now starting with a frame i got for free from an 89 wrangler. I found a 78 or 79 jeep cherokee chief with dana 44s front and rear and a 360 for $300.00. anyway my question is i want to run 39 inch tires and want to know if you guys think the axles are strong enough to handle them rock crawling.  

with a 4cyl and 3.07 gears..  

Is the Cheif a wide track? And does it have a Dana 20 transfercase? (Centered rear Dana 44)  

The dana 44 front I run under my XJ is a (Ford F150)high pinion, and from my understanding is more of less the same as the low pinion out of FSJs. I turn 37's with my front axle without issues. I might add that I have also upgraded to chromoly shafts, ctm's and warn hubs. If all depends on where you wheel and your relationship with the skinny pedal. I live in the southeast where mud covered rocky hillclimbs are abundant, and my driving style is a little "balls to the wall". If throttle is not your friend, I say go for it. Just upgrade the shafts, hubs, and joints first.  

yes the cherokee chief is wide track. is has the quadatrac transfer case but iam going to swap it for a dana 300. The wheeling here in arkansas mainly consist of mud and steep rocky inclines any advice will help guys.  

Then the rear Dana 44 is not centered and won't work for you.

If the front is from a '78, it might have flat top knuckles, and that's good. But, if it's a '79, it won't. Not as good.  

ok thanks