I just did the LS1 swap. Bellhousing to go from the T150 to the 350. If you had the 4cyl 151 you could use it. They do sell bellhousings that can connect up to your clutch linkage. That's a good idea. The radaitor's in's and out's are a little further away than the Amc was. I ran Z28 electric fans then the stainless flex hose. I used 24" for the bottom line and 12" to the top. Ok the Chevy swap can snowball on you, but if you can get the motor Cheap and don't mind the work, go for it. That makes one more CJ on the road. which is a good thing.
Or the 360, which is a fine motor. Make sure you get all of the parts. That front cover can cost you 300. With the 360 you'll just need motor mounts. Maybe upgrade the radiator, exhaust also.
1979 CJ5 LS1, NV4500