Has any one put a Amc V8 in a small Cherokee?? If so did u fab your own motor mounts??

No one should ever say something "can't" be done, every damn fool will surely try it then. The question is more should you? The weight from v8 to I6 is close enough to not worry about that, but space, cooling, torque (will tear up the unibody), major reinforcing to motor mounts, what trans behind it? all need to be asked. I've seen a 454 XJ in Moab.
I spent some time talking with the guy who built it.
Firewall mods are extensive, including moving heater/ac box, tucking the distributer under the cowl (AMC is up front) major mods to fit a huge 5 row radiator..
Coil overs with full width HP D60s axles, TH400 trans, atlas2..
It sure looked cool and was done well, but it aint no small feat. Most V8 xjs head to the scrapper because the platform is weak and most don't take time/money to do them right.

Good luck with the build, but I'd recomend starting with a rig that has a frame.

SD

Thanks for the help, infact i saw a 454 XJ in JP and thats where i got the idea and its unique to have a V8 in an XJ around here. Now I have in my grasps a T-18 and a 20 transfer case no prob there. I currently doing my research on J-20 axles(D60 and D44)to go under it.the width(67") could be a problem cause i don't want to cut um down at all. back to motor mounts is an XJ frame rails the same as a YJ???

Was the 454 XJ bright yellow?

Frames? A yj has one, an XJ does not.
XJ is a unibody, the frame and the body are one piece.
What that means to a project like yours is, extensive reinforcing.
The yellow XJ has 3/16 plate lining most of the under side rails. Yup, it gains a lot of weight too.

Leave the axles full width.

The best rear J20 axle is the semi float 35 spline D60 with a 5 on 5.5 wheel pattern. The full float is a weak 30 spline d 60.

SD

I think it was grey with 454 on the side of the fender. I understand bout under the body, but where the engine mounts theres gotta be rails right???
And the d-60 is 8 bolt does that mean its full floating? whats the diff between full and semi??

Have a look under the hood and under the rest of an XJ, once you look close, "frame" won't be a word you use.
There really is not one to be found.

Semi float: the weight of the rig rests on the axle shafts.

Full float: the weight rests on a wheel hub/spindle and the axle shaft bolts in independently.

Full float D60s don't EVER come stock with 35 spline shafts.
Rather, they come with, weak, 30 spline shafts, not worth running.

Both can be built to be bomber strong, semi float less expensive to do. The advantage of full float is if you do break a shaft, the shaft can be removed without even taking the tire off.

SD

some friends of mine with too much time & energy & way too much imagination built a 383 six pack in a 94 xj & that went over like a lead balloon! twisted all sorts of stuff even after they did alot of welding LOL . then the guru's built a cummins turbo diesel xj out of a 2000. that one worked ok for about 2 months until they hooked up a bully dog kit to it. the time money & energy spent is enough to make you say WOW!
you can build & buy 4.0's that will rock a mustang.

i have a 93 4 door xj with a 3 inch custom lift & a 4.6 stroker that i had built. i can run 5.0 stock stangs for 1/8 of a mile before they get me. but they cant touch me in the woods!!!!