Hi, evercloud! Here is a Wikipedia account of the horsepower and torque ratings on the 2.5L TBI versus MPI engine. The carbureted version was used in 1983-86 Jeep CJ models:
AMC 150/2.5 Compression Horsepower Torque:
One-barrel carburetor 9.2:1 105 hp (78 kW; 106 PS) at 5,000 132 lb·ft (179 N·m) at 2,800
Throttle body injection (TBI) 9.2:1 117 hp (87 kW; 119 PS) at 5,000 135 lb·ft (183 N·m) at 3,500
Multi-point fuel injection (MPFI) 9.1:1 120 hp (89 kW; 122 PS) at 5,250 139 lb·ft (188 N·m) at 3,250
There is no account of a 76 kW variant. Perhaps you found a reference to the late 'seventies to 1983 carbureted G.M. 2.5L four (Iron Duke) used in Jeep CJ models. Here is some information on that engine:
What I find very interesting is the relatively insignificant horsepower gains one could expect from an MPI conversion on the 2.5L AMC four. In fact, other changes beyond just the MPI improvement could account for the difference between 1984-90 (TBI) and 1991-up (MPI). Worth noting, the MPI 2.5L develops maximum torque at a lower rpm, and the TBI develops maximum horsepower at a lower rpm. Not dramatically different speeds in either case, though.
Both engines need to spin quite fast to develop peak horsepower and torque. I recall this from testing the new TJ Wrangler in 1997, comparing the 4.0L six's performance to the 2.5L four. I wondered why Jeep did not strive for more low-end power in the 2.5L pushrod engine. These higher speed power peaks were the trend for import engines, and Jeep was in step with the competition at least. I found that holding the 2.5L MPI four in lower gears on long grades, just to keep up with traffic, did little for fuel efficiency.
There are a number of upgrade possibilities for the 2.5L TBI engine that would even the horsepower and torque without doing an MPI conversion. Air intake and exhaust improvements, in particular, could make up the horsepower and torque.
So, rather than plunge into an involved MPI conversion or a 2.5L MPI engine swap, I would consider some moderate engine upgrades to the 2.5L TBI setup. One example would be a cold air intake. My son-in-law made the system depicted here from a Honda AEM kit:
For exhaust, I could not turn up an aftermarket header for the 1987-90 2.5L TBI engine. Perhaps another member knows a source. For the '91-up MPI 2.5L, there are several header sources.
For the TBI engine, I would concentrate on a performance catalytic converter and open up the exhaust system with a custom head pipe and smoother flowing pipe to the cat and muffler. Use a performance muffler and a less restrictive, smoother tailpipe.
Here is a Random Technologies lower restriction cat installation on the magazine's 4.0L exhaust system. This provides some ideas:
These basic modifications could be easily "reversed" if necessary. The gains would be measurable and certainly equal to or exceed the stock output of a 2.5L MPI engine.
If the engine is in top condition, turbocharging might be a consideration. There is also some potential gain from a custom grind camshaft; however, a higher rpm torque or horsepower gain would be of less value than the bottom end and mid-range power boost of turbocharging.
Turbocharger boost would have to be very mild at the current 9.2:1 compression. A lower compression ratio would be desirable for turbocharging, and this could be accomplished with either a thicker head gasket height or piston changes.