Hi all. New guy here and new to Jeeps as well.
I bought a 1990 2 door 2wd Jeep Cherokee with the 4.0 and a 5 speed that doesn't run due to electrical issues. I'm pulling and tossing the engine and trans anyway to shove in a 400 sbc/th350 combo rated at @ 435 on my last dyno pulls.
My questions are about the rear end and the unibody. Like what rear end is in it and how strong is it? Should I go ahead and do a swap to an 8.8 ford rear? (I have one already with 3.73 and ls)
Is the unibody design pretty strong in these things or do I need to do some sort of bracing?
Thanks for any help. When I get all my ducks in a row and start on it I will keep everyone posted.

 

Hard to say what axle you have it's likely a Dana 35 and it's junk for what your looking at doing, however, take a picture and post it up a lot easier to identify that way.
Their are several companies that offer uniframe reinforcement, check the vendor section here and you can get an idea. A lot of people say they are required but I believe that depends on what you plan on doing with the jeep. Is this a drag jeep, rally jeep, crawler, etc. etc.

 

If its a street jeep use the xj 8.25 if you don't have one now.Drag racer you could go 8.8 swap or currie makes a 9 inch housing.For drag racing i rather have the 9 inch so i can have a few 3rd members geared differently and its easy to swap out a 3rd member once you pull both axles.

 

Another thing you may want to consider is the condition of the rear leaf springs. If they have gone flat (which is not uncommon), you could get axle wrap with that much power to the rear.

Regarding which rear you have, it will be one of these two options:



The one on the left is a Chrysler 8.25. It is most easily identified by the flat bottom on the pumpkin. The Dana 35 on the right has a rounded bottom.

If you have the 8.25, it can probably handle the power. The Dana 35 likely will not. If you have the D35, the 8.25 is a direct bolt-in swap (unless you have ABS, in which case you have to disconnect it with the 8.25).

If you can weld, there are weld-on kits available with all the brackets already made for an 8.8 swap. If you already have one, you might as well use it.

 

Ok mine has the Dana in it. It goes in the scrap pile with the 4.0 and the 5 speed.