so im looking to replace my 89 YJ Sahara's engine and im debating between the AMC 390 or 360

right now i have the 258 cu in (4.2 L) in-line six with what i believe is a Aisin-Warner AX15 manual transmission and a NP231 transfer case, all stock

i did some research on the AMC 390 and got pretty hyped up about it
to my knowledge it bolts right into the same brackets as my 258 and fits right onto my transmission.
unfortunately the price and the rarity of the engine seem to be working against me

from what ive seen 360s are much more common and cheaper. my biggest concern is, will it fit in my yj easily? i cant seem to find anyone's step by step accounts of this swap out nor any information on what needs to be done to make it work

any clarification or information would be greatly appreciated