Not entirely true... in the motor pretty much yes, but unless you get a newer YJ crank, you need to have the snout machined down about 1/4". If you're running a stroker, you also need new(larger) injectors. If he's got a BA 10/5, he's also going to need to find an AX-15. BA 10/5 will not last long behind a stroker.
I did just a gasket set in my 88 4.0, which was all I need.
Why does your motor need a rebuild? I would tear it down, and see how everything is in there before you start buying stuff up. If all you need is gaskets and new bearings, it shouldn't run you more than $200.(If you do the work yourself)