4.0 Heads, Latest Year?

ANY of them need the same thing -- the triangular ports on the passenger side need to be plugged, unless you have a 1987 or later 258 block. Those blocks were cast slightly wider than the older blocks. The last heads flow better at low lift/pm than the earlier heads even though they have the smallest ports. Though small, the ports have a much better shape than earlier models. The heads were developed specifically to deliver their best power in mid ranges -- 1500-3000 rpm -- where most driving is done. They start to fall off over 3500 rpm. They are really great street heads, arguably the best, but not good if you plan on drag racing and need power at 5000rpm (the small port head still makes power up to 5000, but the power curve starts to drop those last 1500 rpm).

Use the 4.0L or 258 pushrods in a 71 or later 232/258. If you have a pre 71 block you need to measure for what pushrods to use -- they are shorter. Someone on here has done it, don't recall what pushrods he used. It's on here somewhere...

Here's a good article on 4.0 changes. The 0331 head was used through end of production in 2006.
http://www.greatlakes4x4.com/showthread.php?t=661
The only thing to remember is that early 0331 heads were prone to cracking in the center, right between cylinders 3 and 4, on top between the valve springs. Chrysler fixed it, but didn't change the casting number. Instead, they cast TUPY (have no clue what it means) right over the weak spot on mid 2000+ heads. The cracking has only been reported for "early 2000 models" as far as I can find, but 88 models may be affected also. Might not though, could have been a running change that was changed back, or a faulty core...

I've been told the 2 bbl adapters don't work very well, that you're better off finding a 2 bbl intake. Just what I've heard. 

Check your headbolt size on your engine before you spend millions of Pesos on a 4.0 headswap.

That last post is all good! To put the 258 intake on the 4.0L head, file the bottom of the two "ears" that normally go over the dowels so the top of the intake lines up with the top of the ports. The ears will sit on TOP of the dowels in the 4.0L head.

Some Jeep racers use the carb adapters and have had no issues. In general carb adapters aren't the best way to go because they can create a choke points and limit performance. All will eventually, but for street use they shouldn't be an issue. You will have to plug the injector ports in a 4.0L intake though. Since you have the 258 carb intake you may as well use it. You will need to make custom washers to clamp the intake and exhaust manifolds on. I used 1/8" thick, 1" wide bar stock cut in about 1" lengths, then filed/ground to fit each location.

No way all the head swap costs are going to be cheaper than a machine shop fee for surfacing .010 off the existing head. That costs about 35 dollars here. A rebuild might be cheap since I'd bet the guides and valves are ok. Sure you might notice a bit more power, but not enough for all the hassle you're about to inflict on yourself trying to figure this swap out without the skills to do so. Just getting the original off and back on sounds like enough challenge.

Just my observation based on what you've posted about your situation.