This is my son's build. With only $2,000. He bought a 1991 YJ Wrangler with a blown 2.5L engine. The PO owner said he could not start it and didn't know what was wrong. We drug it home found a dead fuel pump and had it running within hours but with a really bad rod knock. The crank was unsalvagable so we rebuilt her, painted her in the garage, herculined the tub and off he went.
After saving up for a few years he wanted to swap in a 4.0. I advised he just sell and buy a new Jeep. He protested that he didn't want to for sentimental reasons.

Recipe:
4.2 crank (the old heavy one) $260
Russ's custom forged .030 piston and rod set $325 compression height 1.385, dish volume 26cc. (The combustion chambers were a smidge over 58cc)
CompCams 68-232-4 206/212 (new SLP VS 1456 springs)
DIY ported ported HO 0630 1.91/1.50 58.2 cc (surfaced only) head
.051 felpro composite head gasket
.043 quench
0280155715 Bosch EV6CL 24.7 lb @43 psi injectors
Whole bunch of stock replacement parts from Russ (his prices are as good or better than amazon and eBay apples to apples).
Waiting on block machining.
Any advice or observations are more than welcome.