Hey,
My mechanic stopped short of going to that level of inspection. I've heard engines are in the $1500 - $2300 range.
Are you thinking SFA swap? I'd refer you to LOSTKJS.com for info/build threads. Search for Wally or JJSKJ.
You need a lot of lift to get a solid axle under the engine cradle on a KJ. It sits low - ideal for IFS, not so much for a solid. There's quite a few that have done it though.
Todd