Replacing an engine is not as hard as it is time consuming. Marking everything before removing the old one will be your saving grace later. Really depends on your mechanical ability and having the tools, help and space to do it in. As for cost, it depends on your local area and other variables. I have heard of people having it done for $500 bucks up to $2500. Times are hard, shops aren't as busy that leads to better prices, UNLESS you are a dealer
With a machine shop you are depending on the machinist - to know what he's doing, to be able to operate the machines correctly, and to know what's good vs bad.
But you may save a few bucks.
A new motor directly from Jeep was made on the assembly line that's made tens of thousands of them. They cost more, but you get totally new.
I've always had good luck with new, can't say the same for rebuilts.
My opinion, get a new short block from the dealer - shop around, their prices do vary. Get your head rebuilt by someone with an excellent reputation.
Or - there's a place in Texas that sells inexpensive new loaded heads. Look in magazines for their advertisements.
It's no wonder the country is falling apart - stupidity abounds!
The AMC 4.0L is a brickhouse so acquiring one that is in good condition at a cheap price is incredibly difficult. For the money that you're going to spending, I would honestly consider swapping in a Chevy or a GM small-block engine. Novak makes an excellent guide as well as some nice brackets that bolt the engine right into the bay. After that, it's a matter of dealing with the PCM, the wiring, the gauges, and the tranny hookup. Novak pretty much has all of that covered, but they do charge a small premium.
Finding a GM or Chevy engine in rebuilt or good condition isn't difficult. A decent LM7 can be had for $600 and then it's just a matter of locating some accesories and then buying the proper mounts and converters.
If it's a matter of doing it yourself or paying a shop, I'm in the opinion that it's always better to do it yourself. As stated, engine swaps sound more daunting then they really are. They're just time consuming and can be a pretty simple job if you just mark everything as you go along and take your time! That said, plan to have a 2nd car to use because you might be spending up to a month of free time trying to get everything together. If that sounds like a problem, then a shop is definitely the way to go. Shop around and let garages know what you're looking for specifically. Some have hookups with the local part shops and yards (mine is brothers with the local NAPA guy).
__________________ It's got a Willy's body, a Chevy engine, Ford axles, GM transmission, and Dodge steering components... it must be a Wrangler.
What ever happened to staying brand loyal? The benefits of stroking the 4.0L are worth consideration, no wiring changes, no computer replacement, no custom motor mounts, etc. When you open the hood, it looks like a factory motor, all the changes are on the inside. In my opinion, unless you are going to build your ride to compete in the next King of the Hammers race, just stroke it. The HP & torque figures of even a mild 4.6L engine give you a power to weight ratio equal to the average V8 pickup on the road today. Combine that with gearing to compensate for your tire choices and you have all the power most people will ever need. Once again, just my opinion.
If Mother-in-laws were flowers.......I'd spray mine with ROUND-UP!