I would strongly suggest going with MPFI over even a weber or MC2100 carb. I've run, and still have, webers and Motorcraft carburetors on a few Jeeps and while they are a huge improvement over a typical carter BBD (and more budget friendly), they don't even compare to driving a Jeep with MPFI; in my experience. There is a reason most of my Jeeps are getting junkyard MPFI now.
The 91-95 systems are easy to work on, and once you get to know your way around the wiring its a relatively simple system that runs amazingly well. I feel more confident now working with the MPFI than carburetors; they really are that simple. And if you go the junkyard route the price isn't to bad.
One option you may consider is running the 91-95 4.0 head and MPFI system on the 4.2 block. I have an '85 CJ7 with this setup (with some additional porting/polishing and different injectors) and the Jeep flat out screams going down the road. It feels like it has substantially more power than my other 4.2 or 4.0 powered Jeeps and makes the best mileage out of all of them (even over my '05 LJ and '00 XJ).
I'm currently doing a complete 4.0 swap in one of my Postals so I can't compare directly a 4.0 head swap vs the entire 4.0 engine transplant. But regardless, the MPFI greatly improves the drivability of the Jeeps. It looks like I'm about two hours west of you, let me know if you have any questions on any of this. Or, if you ever make it out this way feel free to stop by and take the CJ7 with 4.0 head and MPFI for a spin to feel the difference for yourself!
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