The below setup will run on 87 octane, and provides more torque, but the engine would have to be bored .030:
4.6L Low-buck, low CR "rockcrawler"
~ Jeep 4.2L 3.895" stroke crank
~ Jeep 4.2L 5.875" rods
~ Keith-Black Silvolite UEM-2229 +0.030" bore pistons
~ Increase piston dish volume to 30cc
~ Crane #750501 192/204 degree camshaft
~ Ported HO 1.91"/1.50" cylinder head
~ Mill block deck 0.035"
~ Mopar Performance 0.043" head gasket
~ 0.058" quench height
~ 2.25" exhaust
~ Stock injectors with stock 49psi FPR for '96 and later engines
~ 231hp @ 4400rpm, 327lbft @ 2000rpm
Another stroker writeup:
This combination is supposed to work with the stock computer and injectors.
You will note that hp is only approximately 40 hp higher than a stock 4.0 liter, but look at the torque. Torque is up about 90 ft-lbs and it comes in 1200 rpm lower than the stock engine is rated.
This is what an increase in displacement does for you - torque increases and it increases at a lower engine speed. This is what you want in a Jeep. This would be no more difficult to do than a stock rebuild and should perform like jack the bear in a Jeep.
I have not tried this combo, but after researching it, I think it should be a good one.