 Fan upgrade is necessary....  Fan upgrade is necessary. 2.5L fan (left) has one less blade and a much smaller diameter. You must upgrade to a six-cylinder fan and fan clutch. Six-cylinder MPI engine has considerably more horsepower and torque than the 2.5L four. Horsepower is BTUs, and a six-cylinder "air conditioning" radiator is advisable. |  Alternator and alternator...  Alternator and alternator bracket are the stock pieces from the '87 YJ Wrangler. You should be able to maintain your factory alternator and brackets if swapping a 2.5L to a 4.0L six. (The late 2.4L four uses different mounting methods.) This engine bay now looks like a stock '94-'95 YJ. |  Front view of engine looks...  Front view of engine looks stock six-cylinder. A new radiator and fan shroud bring the cooling to six-cylinder standards. Power steering pump is Mopar rebuilt unit for six-cylinder engines. Factory or locally fabricated hoses will complete the power steering changes as needed. Stock power steering requires slight modification to return hose's pipe length. |
 The 4.0L engine rests in place...  The 4.0L engine rests in place of the four. Using Mopar's EFI conversion provided the intake/induction system, a full engine wiring harness, crankshaft pulley, and sensor pickup. Most components are '94-'95 YJ Wrangler pieces with the addition of a later single-rail MPI upgrade. On this YJ, the '87 fuel tank and pump assembly were upgraded to '91-'95 components. Specify 15- or 20-gallon tank depth for the pump and sender. |  Engine through transfer case...  Engine through transfer case is now in place. The fresh AX-15 will use a '94-up external clutch slave cylinder. Transfer case is an Advance Adapters Atlas II. An NP/NV231 23-spline would also work. Rear CV driveline accommodates the chassis lift. New front and rear drivelines were built to meet length and design requirements. Exhaust system can be fitted with factory-type six-cylinder pipes, catalytic converter, muffler, and tailpipe. |  Here is the installed, run-ready...  Here is the installed, run-ready engine. A custom bracket at the firewall supports the Mopar EFI Conversion Kit's '95 YJ-style computer. This is a trail-oriented Wrangler with lots of accessories and add-ons. The 180-plus horsepower is welcome. If you have the equipment, skill and good reasons to make this conversion, the gains are clear. |