Any difference in 4.0 by year?
 

I have a '94' motor I was wondering if there's anything I should know before I swap it into a '88' Cherokee. Everything looks the same just different intake dist. ect. But the block and head look the same.

The 88 is controled by a Renix system and the 94 is controled by a Chrysler system. The block is the same and the head is basically the same with some minor differences in how well it flows intake and exhaust. You can use the 94 engine but would have to reuse the 88 intake manifold, exhaust manifold, all the accessory mounts, sensors, and fuel injection system. The 94 head will work in the 88 but will not flow as well with the Renix intake. I tansplanted a 94 engine into my 87 and had it running, but it never ran perfect. I never tried to finish the project due to the rest of the vehicle being junk anyway and stripped the whole thing for parts. It can be done but expect to spend a little time tweeking and fine tuning once you get it fired up.