Been watching a lot of late 90’s early 00’s Outlaws with the Mopar A8 aluminum block that was beating up on them chevys. Now I have the idea of swapping out the 4.0L for a small block A8 bored 410ci once the time comes in the very distant future to make my XJ a weekend toy. Would this be a possibility?

Lots of fab skills and even more money will have it done in a jiffy.

I agree. You will need lots of fab skills, just like any V8 conversion into an XJ. Plan on a tranny swap too, a built tranny